/*
 * Copyright (C) 2007-2010 Advanced Micro Devices, Inc.
 * Author: Joerg Roedel <jroedel@suse.de>
 *         Leo Duran <leo.duran@amd.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/ratelimit.h>
#include <linux/pci.h>
#include <linux/pci-ats.h>
#include <linux/bitmap.h>
#include <linux/slab.h>
#include <linux/debugfs.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/iommu-helper.h>
#include <linux/iommu.h>
#include <linux/delay.h>
#include <linux/amd-iommu.h>
#include <linux/notifier.h>
#include <linux/export.h>
#include <linux/irq.h>
#include <linux/msi.h>
#include <linux/dma-contiguous.h>
#include <linux/irqdomain.h>
#include <linux/percpu.h>
#include <asm/irq_remapping.h>
#include <asm/io_apic.h>
#include <asm/apic.h>
#include <asm/hw_irq.h>
#include <asm/msidef.h>
#include <asm/proto.h>
#include <asm/iommu.h>
#include <asm/gart.h>
#include <asm/dma.h>

#include "amd_iommu_proto.h"
#include "amd_iommu_types.h"
#include "irq_remapping.h"

#define CMD_SET_TYPE(cmd, t) ((cmd)->data[1] |= ((t) << 28))

#define LOOP_TIMEOUT    100000

/*
 * This bitmap is used to advertise the page sizes our hardware support
 * to the IOMMU core, which will then use this information to split
 * physically contiguous memory regions it is mapping into page sizes
 * that we support.
 *
 * 512GB Pages are not supported due to a hardware bug
 */
#define AMD_IOMMU_PGSIZES       ((~0xFFFUL) & ~(2ULL << 38))

static DEFINE_RWLOCK(amd_iommu_devtable_lock);

/* List of all available dev_data structures */
static LIST_HEAD(dev_data_list);
static DEFINE_SPINLOCK(dev_data_list_lock);

LIST_HEAD(ioapic_map);
LIST_HEAD(hpet_map);

/*
 * Domain for untranslated devices - only allocated
 * if iommu=pt passed on kernel cmd line.
 */
static const struct iommu_ops amd_iommu_ops;

static ATOMIC_NOTIFIER_HEAD(ppr_notifier);
int amd_iommu_max_glx_val = -1;

static struct dma_map_ops amd_iommu_dma_ops;

/*
 * This struct contains device specific data for the IOMMU
 */
struct iommu_dev_data {
        struct list_head list;            /* For domain->dev_list */
        struct list_head dev_data_list;   /* For global dev_data_list */
        struct protection_domain *domain; /* Domain the device is bound to */
        u16 devid;                        /* PCI Device ID */
        u16 alias;                        /* Alias Device ID */
        bool iommu_v2;                    /* Device can make use of IOMMUv2 */
        bool passthrough;                 /* Device is identity mapped */
        struct {
                bool enabled;
                int qdep;
        } ats;                            /* ATS state */
        bool pri_tlp;                     /* PASID TLB required for
                                             PPR completions */
        u32 errata;                       /* Bitmap for errata to apply */
};

/*
 * general struct to manage commands send to an IOMMU
 */
struct iommu_cmd {
        u32 data[4];
};

struct kmem_cache *amd_iommu_irq_cache;

static void update_domain(struct protection_domain *domain);
static int protection_domain_init(struct protection_domain *domain);
static void detach_device(struct device *dev);

/*
 * For dynamic growth the aperture size is split into ranges of 128MB of
 * DMA address space each. This struct represents one such range.
 */
struct aperture_range {

        spinlock_t bitmap_lock;

        /* address allocation bitmap */
        unsigned long *bitmap;
        unsigned long offset;
        unsigned long next_bit;

        /*
         * Array of PTE pages for the aperture. In this array we save all the
         * leaf pages of the domain page table used for the aperture. This way
         * we don't need to walk the page table to find a specific PTE. We can
         * just calculate its address in constant time.
         */
        u64 *pte_pages[64];
};

/*
 * Data container for a dma_ops specific protection domain
 */
struct dma_ops_domain {
        /* generic protection domain information */
        struct protection_domain domain;

        /* size of the aperture for the mappings */
        unsigned long aperture_size;

        /* aperture index we start searching for free addresses */
        u32 __percpu *next_index;

        /* address space relevant data */
        struct aperture_range *aperture[APERTURE_MAX_RANGES];
};

/****************************************************************************
 *
 * Helper functions
 *
 ****************************************************************************/

static struct protection_domain *to_pdomain(struct iommu_domain *dom)
{
        return container_of(dom, struct protection_domain, domain);
}

static inline u16 get_device_id(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);

        return PCI_DEVID(pdev->bus->number, pdev->devfn);
}

static struct iommu_dev_data *alloc_dev_data(u16 devid)
{
        struct iommu_dev_data *dev_data;
        unsigned long flags;

        dev_data = kzalloc(sizeof(*dev_data), GFP_KERNEL);
        if (!dev_data)
                return NULL;

        dev_data->devid = devid;

        spin_lock_irqsave(&dev_data_list_lock, flags);
        list_add_tail(&dev_data->dev_data_list, &dev_data_list);
        spin_unlock_irqrestore(&dev_data_list_lock, flags);

        return dev_data;
}

static struct iommu_dev_data *search_dev_data(u16 devid)
{
        struct iommu_dev_data *dev_data;
        unsigned long flags;

        spin_lock_irqsave(&dev_data_list_lock, flags);
        list_for_each_entry(dev_data, &dev_data_list, dev_data_list) {
                if (dev_data->devid == devid)
                        goto out_unlock;
        }

        dev_data = NULL;

out_unlock:
        spin_unlock_irqrestore(&dev_data_list_lock, flags);

        return dev_data;
}

static int __last_alias(struct pci_dev *pdev, u16 alias, void *data)
{
        *(u16 *)data = alias;
        return 0;
}

static u16 get_alias(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        u16 devid, ivrs_alias, pci_alias;

        devid = get_device_id(dev);
        ivrs_alias = amd_iommu_alias_table[devid];
        pci_for_each_dma_alias(pdev, __last_alias, &pci_alias);

        if (ivrs_alias == pci_alias)
                return ivrs_alias;

        /*
         * DMA alias showdown
         *
         * The IVRS is fairly reliable in telling us about aliases, but it
         * can't know about every screwy device.  If we don't have an IVRS
         * reported alias, use the PCI reported alias.  In that case we may
         * still need to initialize the rlookup and dev_table entries if the
         * alias is to a non-existent device.
         */
        if (ivrs_alias == devid) {
                if (!amd_iommu_rlookup_table[pci_alias]) {
                        amd_iommu_rlookup_table[pci_alias] =
                                amd_iommu_rlookup_table[devid];
                        memcpy(amd_iommu_dev_table[pci_alias].data,
                               amd_iommu_dev_table[devid].data,
                               sizeof(amd_iommu_dev_table[pci_alias].data));
                }

                return pci_alias;
        }

        pr_info("AMD-Vi: Using IVRS reported alias %02x:%02x.%d "
                "for device %s[%04x:%04x], kernel reported alias "
                "%02x:%02x.%d\n", PCI_BUS_NUM(ivrs_alias), PCI_SLOT(ivrs_alias),
                PCI_FUNC(ivrs_alias), dev_name(dev), pdev->vendor, pdev->device,
                PCI_BUS_NUM(pci_alias), PCI_SLOT(pci_alias),
                PCI_FUNC(pci_alias));

        /*
         * If we don't have a PCI DMA alias and the IVRS alias is on the same
         * bus, then the IVRS table may know about a quirk that we don't.
         */
        if (pci_alias == devid &&
            PCI_BUS_NUM(ivrs_alias) == pdev->bus->number) {
                pdev->dev_flags |= PCI_DEV_FLAGS_DMA_ALIAS_DEVFN;
                pdev->dma_alias_devfn = ivrs_alias & 0xff;
                pr_info("AMD-Vi: Added PCI DMA alias %02x.%d for %s\n",
                        PCI_SLOT(ivrs_alias), PCI_FUNC(ivrs_alias),
                        dev_name(dev));
        }

        return ivrs_alias;
}

static struct iommu_dev_data *find_dev_data(u16 devid)
{
        struct iommu_dev_data *dev_data;

        dev_data = search_dev_data(devid);

        if (dev_data == NULL)
                dev_data = alloc_dev_data(devid);

        return dev_data;
}

static struct iommu_dev_data *get_dev_data(struct device *dev)
{
        return dev->archdata.iommu;
}

static bool pci_iommuv2_capable(struct pci_dev *pdev)
{
        static const int caps[] = {
                PCI_EXT_CAP_ID_ATS,
                PCI_EXT_CAP_ID_PRI,
                PCI_EXT_CAP_ID_PASID,
        };
        int i, pos;

        for (i = 0; i < 3; ++i) {
                pos = pci_find_ext_capability(pdev, caps[i]);
                if (pos == 0)
                        return false;
        }

        return true;
}

static bool pdev_pri_erratum(struct pci_dev *pdev, u32 erratum)
{
        struct iommu_dev_data *dev_data;

        dev_data = get_dev_data(&pdev->dev);

        return dev_data->errata & (1 << erratum) ? true : false;
}

/*
 * This function actually applies the mapping to the page table of the
 * dma_ops domain.
 */
static void alloc_unity_mapping(struct dma_ops_domain *dma_dom,
                                struct unity_map_entry *e)
{
        u64 addr;

        for (addr = e->address_start; addr < e->address_end;
             addr += PAGE_SIZE) {
                if (addr < dma_dom->aperture_size)
                        __set_bit(addr >> PAGE_SHIFT,
                                  dma_dom->aperture[0]->bitmap);
        }
}

/*
 * Inits the unity mappings required for a specific device
 */
static void init_unity_mappings_for_device(struct device *dev,
                                           struct dma_ops_domain *dma_dom)
{
        struct unity_map_entry *e;
        u16 devid;

        devid = get_device_id(dev);

        list_for_each_entry(e, &amd_iommu_unity_map, list) {
                if (!(devid >= e->devid_start && devid <= e->devid_end))
                        continue;
                alloc_unity_mapping(dma_dom, e);
        }
}

/*
 * This function checks if the driver got a valid device from the caller to
 * avoid dereferencing invalid pointers.
 */
static bool check_device(struct device *dev)
{
        u16 devid;

        if (!dev || !dev->dma_mask)
                return false;

        /* No PCI device */
        if (!dev_is_pci(dev))
                return false;

        devid = get_device_id(dev);

        /* Out of our scope? */
        if (devid > amd_iommu_last_bdf)
                return false;

        if (amd_iommu_rlookup_table[devid] == NULL)
                return false;

        return true;
}

static void init_iommu_group(struct device *dev)
{
        struct dma_ops_domain *dma_domain;
        struct iommu_domain *domain;
        struct iommu_group *group;

        group = iommu_group_get_for_dev(dev);
        if (IS_ERR(group))
                return;

        domain = iommu_group_default_domain(group);
        if (!domain)
                goto out;

        dma_domain = to_pdomain(domain)->priv;

        init_unity_mappings_for_device(dev, dma_domain);
out:
        iommu_group_put(group);
}

static int iommu_init_device(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct iommu_dev_data *dev_data;

        if (dev->archdata.iommu)
                return 0;

        dev_data = find_dev_data(get_device_id(dev));
        if (!dev_data)
                return -ENOMEM;

        dev_data->alias = get_alias(dev);

        if (pci_iommuv2_capable(pdev)) {
                struct amd_iommu *iommu;

                iommu              = amd_iommu_rlookup_table[dev_data->devid];
                dev_data->iommu_v2 = iommu->is_iommu_v2;
        }

        dev->archdata.iommu = dev_data;

        iommu_device_link(amd_iommu_rlookup_table[dev_data->devid]->iommu_dev,
                          dev);

        return 0;
}

static void iommu_ignore_device(struct device *dev)
{
        u16 devid, alias;

        devid = get_device_id(dev);
        alias = get_alias(dev);

        memset(&amd_iommu_dev_table[devid], 0, sizeof(struct dev_table_entry));
        memset(&amd_iommu_dev_table[alias], 0, sizeof(struct dev_table_entry));

        amd_iommu_rlookup_table[devid] = NULL;
        amd_iommu_rlookup_table[alias] = NULL;
}

static void iommu_uninit_device(struct device *dev)
{
        struct iommu_dev_data *dev_data = search_dev_data(get_device_id(dev));

        if (!dev_data)
                return;

        if (dev_data->domain)
                detach_device(dev);

        iommu_device_unlink(amd_iommu_rlookup_table[dev_data->devid]->iommu_dev,
                            dev);

        iommu_group_remove_device(dev);

        /* Remove dma-ops */
        dev->archdata.dma_ops = NULL;

        /*
         * We keep dev_data around for unplugged devices and reuse it when the
         * device is re-plugged - not doing so would introduce a ton of races.
         */
}

#ifdef CONFIG_AMD_IOMMU_STATS

/*
 * Initialization code for statistics collection
 */

DECLARE_STATS_COUNTER(compl_wait);
DECLARE_STATS_COUNTER(cnt_map_single);
DECLARE_STATS_COUNTER(cnt_unmap_single);
DECLARE_STATS_COUNTER(cnt_map_sg);
DECLARE_STATS_COUNTER(cnt_unmap_sg);
DECLARE_STATS_COUNTER(cnt_alloc_coherent);
DECLARE_STATS_COUNTER(cnt_free_coherent);
DECLARE_STATS_COUNTER(cross_page);
DECLARE_STATS_COUNTER(domain_flush_single);
DECLARE_STATS_COUNTER(domain_flush_all);
DECLARE_STATS_COUNTER(alloced_io_mem);
DECLARE_STATS_COUNTER(total_map_requests);
DECLARE_STATS_COUNTER(complete_ppr);
DECLARE_STATS_COUNTER(invalidate_iotlb);
DECLARE_STATS_COUNTER(invalidate_iotlb_all);
DECLARE_STATS_COUNTER(pri_requests);

static struct dentry *stats_dir;
static struct dentry *de_fflush;

static void amd_iommu_stats_add(struct __iommu_counter *cnt)
{
        if (stats_dir == NULL)
                return;

        cnt->dent = debugfs_create_u64(cnt->name, 0444, stats_dir,
                                       &cnt->value);
}

static void amd_iommu_stats_init(void)
{
        stats_dir = debugfs_create_dir("amd-iommu", NULL);
        if (stats_dir == NULL)
                return;

        de_fflush  = debugfs_create_bool("fullflush", 0444, stats_dir,
                                         &amd_iommu_unmap_flush);

        amd_iommu_stats_add(&compl_wait);
        amd_iommu_stats_add(&cnt_map_single);
        amd_iommu_stats_add(&cnt_unmap_single);
        amd_iommu_stats_add(&cnt_map_sg);
        amd_iommu_stats_add(&cnt_unmap_sg);
        amd_iommu_stats_add(&cnt_alloc_coherent);
        amd_iommu_stats_add(&cnt_free_coherent);
        amd_iommu_stats_add(&cross_page);
        amd_iommu_stats_add(&domain_flush_single);
        amd_iommu_stats_add(&domain_flush_all);
        amd_iommu_stats_add(&alloced_io_mem);
        amd_iommu_stats_add(&total_map_requests);
        amd_iommu_stats_add(&complete_ppr);
        amd_iommu_stats_add(&invalidate_iotlb);
        amd_iommu_stats_add(&invalidate_iotlb_all);
        amd_iommu_stats_add(&pri_requests);
}

#endif

/****************************************************************************
 *
 * Interrupt handling functions
 *
 ****************************************************************************/

static void dump_dte_entry(u16 devid)
{
        int i;

        for (i = 0; i < 4; ++i)
                pr_err("AMD-Vi: DTE[%d]: %016llx\n", i,
                        amd_iommu_dev_table[devid].data[i]);
}

static void dump_command(unsigned long phys_addr)
{
        struct iommu_cmd *cmd = phys_to_virt(phys_addr);
        int i;

        for (i = 0; i < 4; ++i)
                pr_err("AMD-Vi: CMD[%d]: %08x\n", i, cmd->data[i]);
}

static void iommu_print_event(struct amd_iommu *iommu, void *__evt)
{
        int type, devid, domid, flags;
        volatile u32 *event = __evt;
        int count = 0;
        u64 address;

retry:
        type    = (event[1] >> EVENT_TYPE_SHIFT)  & EVENT_TYPE_MASK;
        devid   = (event[0] >> EVENT_DEVID_SHIFT) & EVENT_DEVID_MASK;
        domid   = (event[1] >> EVENT_DOMID_SHIFT) & EVENT_DOMID_MASK;
        flags   = (event[1] >> EVENT_FLAGS_SHIFT) & EVENT_FLAGS_MASK;
        address = (u64)(((u64)event[3]) << 32) | event[2];

        if (type == 0) {
                /* Did we hit the erratum? */
                if (++count == LOOP_TIMEOUT) {
                        pr_err("AMD-Vi: No event written to event log\n");
                        return;
                }
                udelay(1);
                goto retry;
        }

        printk(KERN_ERR "AMD-Vi: Event logged [");

        switch (type) {
        case EVENT_TYPE_ILL_DEV:
                printk("ILLEGAL_DEV_TABLE_ENTRY device=%02x:%02x.%x "
                       "address=0x%016llx flags=0x%04x]\n",
                       PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
                       address, flags);
                dump_dte_entry(devid);
                break;
        case EVENT_TYPE_IO_FAULT:
                printk("IO_PAGE_FAULT device=%02x:%02x.%x "
                       "domain=0x%04x address=0x%016llx flags=0x%04x]\n",
                       PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
                       domid, address, flags);
                break;
        case EVENT_TYPE_DEV_TAB_ERR:
                printk("DEV_TAB_HARDWARE_ERROR device=%02x:%02x.%x "
                       "address=0x%016llx flags=0x%04x]\n",
                       PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
                       address, flags);
                break;
        case EVENT_TYPE_PAGE_TAB_ERR:
                printk("PAGE_TAB_HARDWARE_ERROR device=%02x:%02x.%x "
                       "domain=0x%04x address=0x%016llx flags=0x%04x]\n",
                       PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
                       domid, address, flags);
                break;
        case EVENT_TYPE_ILL_CMD:
                printk("ILLEGAL_COMMAND_ERROR address=0x%016llx]\n", address);
                dump_command(address);
                break;
        case EVENT_TYPE_CMD_HARD_ERR:
                printk("COMMAND_HARDWARE_ERROR address=0x%016llx "
                       "flags=0x%04x]\n", address, flags);
                break;
        case EVENT_TYPE_IOTLB_INV_TO:
                printk("IOTLB_INV_TIMEOUT device=%02x:%02x.%x "
                       "address=0x%016llx]\n",
                       PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
                       address);
                break;
        case EVENT_TYPE_INV_DEV_REQ:
                printk("INVALID_DEVICE_REQUEST device=%02x:%02x.%x "
                       "address=0x%016llx flags=0x%04x]\n",
                       PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
                       address, flags);
                break;
        default:
                printk(KERN_ERR "UNKNOWN type=0x%02x]\n", type);
        }

        memset(__evt, 0, 4 * sizeof(u32));
}

static void iommu_poll_events(struct amd_iommu *iommu)
{
        u32 head, tail;

        head = readl(iommu->mmio_base + MMIO_EVT_HEAD_OFFSET);
        tail = readl(iommu->mmio_base + MMIO_EVT_TAIL_OFFSET);

        while (head != tail) {
                iommu_print_event(iommu, iommu->evt_buf + head);
                head = (head + EVENT_ENTRY_SIZE) % EVT_BUFFER_SIZE;
        }

        writel(head, iommu->mmio_base + MMIO_EVT_HEAD_OFFSET);
}

static void iommu_handle_ppr_entry(struct amd_iommu *iommu, u64 *raw)
{
        struct amd_iommu_fault fault;

        INC_STATS_COUNTER(pri_requests);

        if (PPR_REQ_TYPE(raw[0]) != PPR_REQ_FAULT) {
                pr_err_ratelimited("AMD-Vi: Unknown PPR request received\n");
                return;
        }

        fault.address   = raw[1];
        fault.pasid     = PPR_PASID(raw[0]);
        fault.device_id = PPR_DEVID(raw[0]);
        fault.tag       = PPR_TAG(raw[0]);
        fault.flags     = PPR_FLAGS(raw[0]);

        atomic_notifier_call_chain(&ppr_notifier, 0, &fault);
}

static void iommu_poll_ppr_log(struct amd_iommu *iommu)
{
        u32 head, tail;

        if (iommu->ppr_log == NULL)
                return;

        head = readl(iommu->mmio_base + MMIO_PPR_HEAD_OFFSET);
        tail = readl(iommu->mmio_base + MMIO_PPR_TAIL_OFFSET);

        while (head != tail) {
                volatile u64 *raw;
                u64 entry[2];
                int i;

                raw = (u64 *)(iommu->ppr_log + head);

                /*
                 * Hardware bug: Interrupt may arrive before the entry is
                 * written to memory. If this happens we need to wait for the
                 * entry to arrive.
                 */
                for (i = 0; i < LOOP_TIMEOUT; ++i) {
                        if (PPR_REQ_TYPE(raw[0]) != 0)
                                break;
                        udelay(1);
                }

                /* Avoid memcpy function-call overhead */
                entry[0] = raw[0];
                entry[1] = raw[1];

                /*
                 * To detect the hardware bug we need to clear the entry
                 * back to zero.
                 */
                raw[0] = raw[1] = 0UL;

                /* Update head pointer of hardware ring-buffer */
                head = (head + PPR_ENTRY_SIZE) % PPR_LOG_SIZE;
                writel(head, iommu->mmio_base + MMIO_PPR_HEAD_OFFSET);

                /* Handle PPR entry */
                iommu_handle_ppr_entry(iommu, entry);

                /* Refresh ring-buffer information */
                head = readl(iommu->mmio_base + MMIO_PPR_HEAD_OFFSET);
                tail = readl(iommu->mmio_base + MMIO_PPR_TAIL_OFFSET);
        }
}

irqreturn_t amd_iommu_int_thread(int irq, void *data)
{
        struct amd_iommu *iommu = (struct amd_iommu *) data;
        u32 status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);

        while (status & (MMIO_STATUS_EVT_INT_MASK | MMIO_STATUS_PPR_INT_MASK)) {
                /* Enable EVT and PPR interrupts again */
                writel((MMIO_STATUS_EVT_INT_MASK | MMIO_STATUS_PPR_INT_MASK),
                        iommu->mmio_base + MMIO_STATUS_OFFSET);

                if (status & MMIO_STATUS_EVT_INT_MASK) {
                        pr_devel("AMD-Vi: Processing IOMMU Event Log\n");
                        iommu_poll_events(iommu);
                }

                if (status & MMIO_STATUS_PPR_INT_MASK) {
                        pr_devel("AMD-Vi: Processing IOMMU PPR Log\n");
                        iommu_poll_ppr_log(iommu);
                }

                /*
                 * Hardware bug: ERBT1312
                 * When re-enabling interrupt (by writing 1
                 * to clear the bit), the hardware might also try to set
                 * the interrupt bit in the event status register.
                 * In this scenario, the bit will be set, and disable
                 * subsequent interrupts.
                 *
                 * Workaround: The IOMMU driver should read back the
                 * status register and check if the interrupt bits are cleared.
                 * If not, driver will need to go through the interrupt handler
                 * again and re-clear the bits
                 */
                status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);
        }
        return IRQ_HANDLED;
}

irqreturn_t amd_iommu_int_handler(int irq, void *data)
{
        return IRQ_WAKE_THREAD;
}

/****************************************************************************
 *
 * IOMMU command queuing functions
 *
 ****************************************************************************/

static int wait_on_sem(volatile u64 *sem)
{
        int i = 0;

        while (*sem == 0 && i < LOOP_TIMEOUT) {
                udelay(1);
                i += 1;
        }

        if (i == LOOP_TIMEOUT) {
                pr_alert("AMD-Vi: Completion-Wait loop timed out\n");
                return -EIO;
        }

        return 0;
}

static void copy_cmd_to_buffer(struct amd_iommu *iommu,
                               struct iommu_cmd *cmd,
                               u32 tail)
{
        u8 *target;

        target = iommu->cmd_buf + tail;
        tail   = (tail + sizeof(*cmd)) % CMD_BUFFER_SIZE;

        /* Copy command to buffer */
        memcpy(target, cmd, sizeof(*cmd));

        /* Tell the IOMMU about it */
        writel(tail, iommu->mmio_base + MMIO_CMD_TAIL_OFFSET);
}

static void build_completion_wait(struct iommu_cmd *cmd, u64 address)
{
        WARN_ON(address & 0x7ULL);

        memset(cmd, 0, sizeof(*cmd));
        cmd->data[0] = lower_32_bits(__pa(address)) | CMD_COMPL_WAIT_STORE_MASK;
        cmd->data[1] = upper_32_bits(__pa(address));
        cmd->data[2] = 1;
        CMD_SET_TYPE(cmd, CMD_COMPL_WAIT);
}

static void build_inv_dte(struct iommu_cmd *cmd, u16 devid)
{
        memset(cmd, 0, sizeof(*cmd));
        cmd->data[0] = devid;
        CMD_SET_TYPE(cmd, CMD_INV_DEV_ENTRY);
}

static void build_inv_iommu_pages(struct iommu_cmd *cmd, u64 address,
                                  size_t size, u16 domid, int pde)
{
        u64 pages;
        bool s;

        pages = iommu_num_pages(address, size, PAGE_SIZE);
        s     = false;

        if (pages > 1) {
                /*
                 * If we have to flush more than one page, flush all
                 * TLB entries for this domain
                 */
                address = CMD_INV_IOMMU_ALL_PAGES_ADDRESS;
                s = true;
        }

        address &= PAGE_MASK;

        memset(cmd, 0, sizeof(*cmd));
        cmd->data[1] |= domid;
        cmd->data[2]  = lower_32_bits(address);
        cmd->data[3]  = upper_32_bits(address);
        CMD_SET_TYPE(cmd, CMD_INV_IOMMU_PAGES);
        if (s) /* size bit - we flush more than one 4kb page */
                cmd->data[2] |= CMD_INV_IOMMU_PAGES_SIZE_MASK;
        if (pde) /* PDE bit - we want to flush everything, not only the PTEs */
                cmd->data[2] |= CMD_INV_IOMMU_PAGES_PDE_MASK;
}

static void build_inv_iotlb_pages(struct iommu_cmd *cmd, u16 devid, int qdep,
                                  u64 address, size_t size)
{
        u64 pages;
        bool s;

        pages = iommu_num_pages(address, size, PAGE_SIZE);
        s     = false;

        if (pages > 1) {
                /*
                 * If we have to flush more than one page, flush all
                 * TLB entries for this domain
                 */
                address = CMD_INV_IOMMU_ALL_PAGES_ADDRESS;
                s = true;
        }

        address &= PAGE_MASK;

        memset(cmd, 0, sizeof(*cmd));
        cmd->data[0]  = devid;
        cmd->data[0] |= (qdep & 0xff) << 24;
        cmd->data[1]  = devid;
        cmd->data[2]  = lower_32_bits(address);
        cmd->data[3]  = upper_32_bits(address);
        CMD_SET_TYPE(cmd, CMD_INV_IOTLB_PAGES);
        if (s)
                cmd->data[2] |= CMD_INV_IOMMU_PAGES_SIZE_MASK;
}

static void build_inv_iommu_pasid(struct iommu_cmd *cmd, u16 domid, int pasid,
                                  u64 address, bool size)
{
        memset(cmd, 0, sizeof(*cmd));

        address &= ~(0xfffULL);

        cmd->data[0]  = pasid;
        cmd->data[1]  = domid;
        cmd->data[2]  = lower_32_bits(address);
        cmd->data[3]  = upper_32_bits(address);
        cmd->data[2] |= CMD_INV_IOMMU_PAGES_PDE_MASK;
        cmd->data[2] |= CMD_INV_IOMMU_PAGES_GN_MASK;
        if (size)
                cmd->data[2] |= CMD_INV_IOMMU_PAGES_SIZE_MASK;
        CMD_SET_TYPE(cmd, CMD_INV_IOMMU_PAGES);
}

static void build_inv_iotlb_pasid(struct iommu_cmd *cmd, u16 devid, int pasid,
                                  int qdep, u64 address, bool size)
{
        memset(cmd, 0, sizeof(*cmd));

        address &= ~(0xfffULL);

        cmd->data[0]  = devid;
        cmd->data[0] |= ((pasid >> 8) & 0xff) << 16;
        cmd->data[0] |= (qdep  & 0xff) << 24;
        cmd->data[1]  = devid;
        cmd->data[1] |= (pasid & 0xff) << 16;
        cmd->data[2]  = lower_32_bits(address);
        cmd->data[2] |= CMD_INV_IOMMU_PAGES_GN_MASK;
        cmd->data[3]  = upper_32_bits(address);
        if (size)
                cmd->data[2] |= CMD_INV_IOMMU_PAGES_SIZE_MASK;
        CMD_SET_TYPE(cmd, CMD_INV_IOTLB_PAGES);
}

static void build_complete_ppr(struct iommu_cmd *cmd, u16 devid, int pasid,
                               int status, int tag, bool gn)
{
        memset(cmd, 0, sizeof(*cmd));

        cmd->data[0]  = devid;
        if (gn) {
                cmd->data[1]  = pasid;
                cmd->data[2]  = CMD_INV_IOMMU_PAGES_GN_MASK;
        }
        cmd->data[3]  = tag & 0x1ff;
        cmd->data[3] |= (status & PPR_STATUS_MASK) << PPR_STATUS_SHIFT;

        CMD_SET_TYPE(cmd, CMD_COMPLETE_PPR);
}

static void build_inv_all(struct iommu_cmd *cmd)
{
        memset(cmd, 0, sizeof(*cmd));
        CMD_SET_TYPE(cmd, CMD_INV_ALL);
}

static void build_inv_irt(struct iommu_cmd *cmd, u16 devid)
{
        memset(cmd, 0, sizeof(*cmd));
        cmd->data[0] = devid;
        CMD_SET_TYPE(cmd, CMD_INV_IRT);
}

/*
 * Writes the command to the IOMMUs command buffer and informs the
 * hardware about the new command.
 */
static int iommu_queue_command_sync(struct amd_iommu *iommu,
                                    struct iommu_cmd *cmd,
                                    bool sync)
{
        u32 left, tail, head, next_tail;
        unsigned long flags;

again:
        spin_lock_irqsave(&iommu->lock, flags);

        head      = readl(iommu->mmio_base + MMIO_CMD_HEAD_OFFSET);
        tail      = readl(iommu->mmio_base + MMIO_CMD_TAIL_OFFSET);
        next_tail = (tail + sizeof(*cmd)) % CMD_BUFFER_SIZE;
        left      = (head - next_tail) % CMD_BUFFER_SIZE;

        if (left <= 2) {
                struct iommu_cmd sync_cmd;
                volatile u64 sem = 0;
                int ret;

                build_completion_wait(&sync_cmd, (u64)&sem);
                copy_cmd_to_buffer(iommu, &sync_cmd, tail);

                spin_unlock_irqrestore(&iommu->lock, flags);

                if ((ret = wait_on_sem(&sem)) != 0)
                        return ret;

                goto again;
        }

        copy_cmd_to_buffer(iommu, cmd, tail);

        /* We need to sync now to make sure all commands are processed */
        iommu->need_sync = sync;

        spin_unlock_irqrestore(&iommu->lock, flags);

        return 0;
}

static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
{
        return iommu_queue_command_sync(iommu, cmd, true);
}

/*
 * This function queues a completion wait command into the command
 * buffer of an IOMMU
 */
static int iommu_completion_wait(struct amd_iommu *iommu)
{
        struct iommu_cmd cmd;
        volatile u64 sem = 0;
        int ret;

        if (!iommu->need_sync)
                return 0;

        build_completion_wait(&cmd, (u64)&sem);

        ret = iommu_queue_command_sync(iommu, &cmd, false);
        if (ret)
                return ret;

        return wait_on_sem(&sem);
}

static int iommu_flush_dte(struct amd_iommu *iommu, u16 devid)
{
        struct iommu_cmd cmd;

        build_inv_dte(&cmd, devid);

        return iommu_queue_command(iommu, &cmd);
}

static void iommu_flush_dte_all(struct amd_iommu *iommu)
{
        u32 devid;

        for (devid = 0; devid <= 0xffff; ++devid)
                iommu_flush_dte(iommu, devid);

        iommu_completion_wait(iommu);
}

/*
 * This function uses heavy locking and may disable irqs for some time. But
 * this is no issue because it is only called during resume.
 */
static void iommu_flush_tlb_all(struct amd_iommu *iommu)
{
        u32 dom_id;

        for (dom_id = 0; dom_id <= 0xffff; ++dom_id) {
                struct iommu_cmd cmd;
                build_inv_iommu_pages(&cmd, 0, CMD_INV_IOMMU_ALL_PAGES_ADDRESS,
                                      dom_id, 1);
                iommu_queue_command(iommu, &cmd);
        }

        iommu_completion_wait(iommu);
}

static void iommu_flush_all(struct amd_iommu *iommu)
{
        struct iommu_cmd cmd;

        build_inv_all(&cmd);

        iommu_queue_command(iommu, &cmd);
        iommu_completion_wait(iommu);
}

static void iommu_flush_irt(struct amd_iommu *iommu, u16 devid)
{
        struct iommu_cmd cmd;

        build_inv_irt(&cmd, devid);

        iommu_queue_command(iommu, &cmd);
}

static void iommu_flush_irt_all(struct amd_iommu *iommu)
{
        u32 devid;

        for (devid = 0; devid <= MAX_DEV_TABLE_ENTRIES; devid++)
                iommu_flush_irt(iommu, devid);

        iommu_completion_wait(iommu);
}

void iommu_flush_all_caches(struct amd_iommu *iommu)
{
        if (iommu_feature(iommu, FEATURE_IA)) {
                iommu_flush_all(iommu);
        } else {
                iommu_flush_dte_all(iommu);
                iommu_flush_irt_all(iommu);
                iommu_flush_tlb_all(iommu);
        }
}

/*
 * Command send function for flushing on-device TLB
 */
static int device_flush_iotlb(struct iommu_dev_data *dev_data,
                              u64 address, size_t size)
{
        struct amd_iommu *iommu;
        struct iommu_cmd cmd;
        int qdep;

        qdep     = dev_data->ats.qdep;
        iommu    = amd_iommu_rlookup_table[dev_data->devid];

        build_inv_iotlb_pages(&cmd, dev_data->devid, qdep, address, size);

        return iommu_queue_command(iommu, &cmd);
}

/*
 * Command send function for invalidating a device table entry
 */
static int device_flush_dte(struct iommu_dev_data *dev_data)
{
        struct amd_iommu *iommu;
        u16 alias;
        int ret;

        iommu = amd_iommu_rlookup_table[dev_data->devid];
        alias = dev_data->alias;

        ret = iommu_flush_dte(iommu, dev_data->devid);
        if (!ret && alias != dev_data->devid)
                ret = iommu_flush_dte(iommu, alias);
        if (ret)
                return ret;

        if (dev_data->ats.enabled)
                ret = device_flush_iotlb(dev_data, 0, ~0UL);

        return ret;
}

/*
 * TLB invalidation function which is called from the mapping functions.
 * It invalidates a single PTE if the range to flush is within a single
 * page. Otherwise it flushes the whole TLB of the IOMMU.
 */
static void __domain_flush_pages(struct protection_domain *domain,
                                 u64 address, size_t size, int pde)
{
        struct iommu_dev_data *dev_data;
        struct iommu_cmd cmd;
        int ret = 0, i;

        build_inv_iommu_pages(&cmd, address, size, domain->id, pde);

        for (i = 0; i < amd_iommus_present; ++i) {
                if (!domain->dev_iommu[i])
                        continue;

                /*
                 * Devices of this domain are behind this IOMMU
                 * We need a TLB flush
                 */
                ret |= iommu_queue_command(amd_iommus[i], &cmd);
        }

        list_for_each_entry(dev_data, &domain->dev_list, list) {

                if (!dev_data->ats.enabled)
                        continue;

                ret |= device_flush_iotlb(dev_data, address, size);
        }

        WARN_ON(ret);
}

static void domain_flush_pages(struct protection_domain *domain,
                               u64 address, size_t size)
{
        __domain_flush_pages(domain, address, size, 0);
}

/* Flush the whole IO/TLB for a given protection domain */
static void domain_flush_tlb(struct protection_domain *domain)
{
        __domain_flush_pages(domain, 0, CMD_INV_IOMMU_ALL_PAGES_ADDRESS, 0);
}

/* Flush the whole IO/TLB for a given protection domain - including PDE */
static void domain_flush_tlb_pde(struct protection_domain *domain)
{
        __domain_flush_pages(domain, 0, CMD_INV_IOMMU_ALL_PAGES_ADDRESS, 1);
}

static void domain_flush_complete(struct protection_domain *domain)
{
        int i;

        for (i = 0; i < amd_iommus_present; ++i) {
                if (!domain->dev_iommu[i])
                        continue;

                /*
                 * Devices of this domain are behind this IOMMU
                 * We need to wait for completion of all commands.
                 */
                iommu_completion_wait(amd_iommus[i]);
        }
}


/*
 * This function flushes the DTEs for all devices in domain
 */
static void domain_flush_devices(struct protection_domain *domain)
{
        struct iommu_dev_data *dev_data;

        list_for_each_entry(dev_data, &domain->dev_list, list)
                device_flush_dte(dev_data);
}

/****************************************************************************
 *
 * The functions below are used the create the page table mappings for
 * unity mapped regions.
 *
 ****************************************************************************/

/*
 * This function is used to add another level to an IO page table. Adding
 * another level increases the size of the address space by 9 bits to a size up
 * to 64 bits.
 */
static bool increase_address_space(struct protection_domain *domain,
                                   gfp_t gfp)
{
        u64 *pte;

        if (domain->mode == PAGE_MODE_6_LEVEL)
                /* address space already 64 bit large */
                return false;

        pte = (void *)get_zeroed_page(gfp);
        if (!pte)
                return false;

        *pte             = PM_LEVEL_PDE(domain->mode,
                                        virt_to_phys(domain->pt_root));
        domain->pt_root  = pte;
        domain->mode    += 1;
        domain->updated  = true;

        return true;
}

static u64 *alloc_pte(struct protection_domain *domain,
                      unsigned long address,
                      unsigned long page_size,
                      u64 **pte_page,
                      gfp_t gfp)
{
        int level, end_lvl;
        u64 *pte, *page;

        BUG_ON(!is_power_of_2(page_size));

        while (address > PM_LEVEL_SIZE(domain->mode))
                increase_address_space(domain, gfp);

        level   = domain->mode - 1;
        pte     = &domain->pt_root[PM_LEVEL_INDEX(level, address)];
        address = PAGE_SIZE_ALIGN(address, page_size);
        end_lvl = PAGE_SIZE_LEVEL(page_size);

        while (level > end_lvl) {
                u64 __pte, __npte;

                __pte = *pte;

                if (!IOMMU_PTE_PRESENT(__pte)) {
                        page = (u64 *)get_zeroed_page(gfp);
                        if (!page)
                                return NULL;

                        __npte = PM_LEVEL_PDE(level, virt_to_phys(page));

                        if (cmpxchg64(pte, __pte, __npte)) {
                                free_page((unsigned long)page);
                                continue;
                        }
                }

                /* No level skipping support yet */
                if (PM_PTE_LEVEL(*pte) != level)
                        return NULL;

                level -= 1;

                pte = IOMMU_PTE_PAGE(*pte);

                if (pte_page && level == end_lvl)
                        *pte_page = pte;

                pte = &pte[PM_LEVEL_INDEX(level, address)];
        }

        return pte;
}

/*
 * This function checks if there is a PTE for a given dma address. If
 * there is one, it returns the pointer to it.
 */
static u64 *fetch_pte(struct protection_domain *domain,
                      unsigned long address,
                      unsigned long *page_size)
{
        int level;
        u64 *pte;

        if (address > PM_LEVEL_SIZE(domain->mode))
                return NULL;

        level      =  domain->mode - 1;
        pte        = &domain->pt_root[PM_LEVEL_INDEX(level, address)];
        *page_size =  PTE_LEVEL_PAGE_SIZE(level);

        while (level > 0) {

                /* Not Present */
                if (!IOMMU_PTE_PRESENT(*pte))
                        return NULL;

                /* Large PTE */
                if (PM_PTE_LEVEL(*pte) == 7 ||
                    PM_PTE_LEVEL(*pte) == 0)
                        break;

                /* No level skipping support yet */
                if (PM_PTE_LEVEL(*pte) != level)
                        return NULL;

                level -= 1;

                /* Walk to the next level */
                pte        = IOMMU_PTE_PAGE(*pte);
                pte        = &pte[PM_LEVEL_INDEX(level, address)];
                *page_size = PTE_LEVEL_PAGE_SIZE(level);
        }

        if (PM_PTE_LEVEL(*pte) == 0x07) {
                unsigned long pte_mask;

                /*
                 * If we have a series of large PTEs, make
                 * sure to return a pointer to the first one.
                 */
                *page_size = pte_mask = PTE_PAGE_SIZE(*pte);
                pte_mask   = ~((PAGE_SIZE_PTE_COUNT(pte_mask) << 3) - 1);
                pte        = (u64 *)(((unsigned long)pte) & pte_mask);
        }

        return pte;
}

/*
 * Generic mapping functions. It maps a physical address into a DMA
 * address space. It allocates the page table pages if necessary.
 * In the future it can be extended to a generic mapping function
 * supporting all features of AMD IOMMU page tables like level skipping
 * and full 64 bit address spaces.
 */
static int iommu_map_page(struct protection_domain *dom,
                          unsigned long bus_addr,
                          unsigned long phys_addr,
                          int prot,
                          unsigned long page_size)
{
        u64 __pte, *pte;
        int i, count;

        BUG_ON(!IS_ALIGNED(bus_addr, page_size));
        BUG_ON(!IS_ALIGNED(phys_addr, page_size));

        if (!(prot & IOMMU_PROT_MASK))
                return -EINVAL;

        count = PAGE_SIZE_PTE_COUNT(page_size);
        pte   = alloc_pte(dom, bus_addr, page_size, NULL, GFP_KERNEL);

        if (!pte)
                return -ENOMEM;

        for (i = 0; i < count; ++i)
                if (IOMMU_PTE_PRESENT(pte[i]))
                        return -EBUSY;

        if (count > 1) {
                __pte = PAGE_SIZE_PTE(phys_addr, page_size);
                __pte |= PM_LEVEL_ENC(7) | IOMMU_PTE_P | IOMMU_PTE_FC;
        } else
                __pte = phys_addr | IOMMU_PTE_P | IOMMU_PTE_FC;

        if (prot & IOMMU_PROT_IR)
                __pte |= IOMMU_PTE_IR;
        if (prot & IOMMU_PROT_IW)
                __pte |= IOMMU_PTE_IW;

        for (i = 0; i < count; ++i)
                pte[i] = __pte;

        update_domain(dom);

        return 0;
}

static unsigned long iommu_unmap_page(struct protection_domain *dom,
                                      unsigned long bus_addr,
                                      unsigned long page_size)
{
        unsigned long long unmapped;
        unsigned long unmap_size;
        u64 *pte;

        BUG_ON(!is_power_of_2(page_size));

        unmapped = 0;

        while (unmapped < page_size) {

                pte = fetch_pte(dom, bus_addr, &unmap_size);

                if (pte) {
                        int i, count;

                        count = PAGE_SIZE_PTE_COUNT(unmap_size);
                        for (i = 0; i < count; i++)
                                pte[i] = 0ULL;
                }

                bus_addr  = (bus_addr & ~(unmap_size - 1)) + unmap_size;
                unmapped += unmap_size;
        }

        BUG_ON(unmapped && !is_power_of_2(unmapped));

        return unmapped;
}

/****************************************************************************
 *
 * The next functions belong to the address allocator for the dma_ops
 * interface functions. They work like the allocators in the other IOMMU
 * drivers. Its basically a bitmap which marks the allocated pages in
 * the aperture. Maybe it could be enhanced in the future to a more
 * efficient allocator.
 *
 ****************************************************************************/

/*
 * The address allocator core functions.
 *
 * called with domain->lock held
 */

/*
 * Used to reserve address ranges in the aperture (e.g. for exclusion
 * ranges.
 */
static void dma_ops_reserve_addresses(struct dma_ops_domain *dom,
                                      unsigned long start_page,
                                      unsigned int pages)
{
        unsigned int i, last_page = dom->aperture_size >> PAGE_SHIFT;

        if (start_page + pages > last_page)
                pages = last_page - start_page;

        for (i = start_page; i < start_page + pages; ++i) {
                int index = i / APERTURE_RANGE_PAGES;
                int page  = i % APERTURE_RANGE_PAGES;
                __set_bit(page, dom->aperture[index]->bitmap);
        }
}

/*
 * This function is used to add a new aperture range to an existing
 * aperture in case of dma_ops domain allocation or address allocation
 * failure.
 */
static int alloc_new_range(struct dma_ops_domain *dma_dom,
                           bool populate, gfp_t gfp)
{
        int index = dma_dom->aperture_size >> APERTURE_RANGE_SHIFT;
        unsigned long i, old_size, pte_pgsize;
        struct aperture_range *range;
        struct amd_iommu *iommu;
        unsigned long flags;

#ifdef CONFIG_IOMMU_STRESS
        populate = false;
#endif

        if (index >= APERTURE_MAX_RANGES)
                return -ENOMEM;

        range = kzalloc(sizeof(struct aperture_range), gfp);
        if (!range)
                return -ENOMEM;

        range->bitmap = (void *)get_zeroed_page(gfp);
        if (!range->bitmap)
                goto out_free;

        range->offset = dma_dom->aperture_size;

        spin_lock_init(&range->bitmap_lock);

        if (populate) {
                unsigned long address = dma_dom->aperture_size;
                int i, num_ptes = APERTURE_RANGE_PAGES / 512;
                u64 *pte, *pte_page;

                for (i = 0; i < num_ptes; ++i) {
                        pte = alloc_pte(&dma_dom->domain, address, PAGE_SIZE,
                                        &pte_page, gfp);
                        if (!pte)
                                goto out_free;

                        range->pte_pages[i] = pte_page;

                        address += APERTURE_RANGE_SIZE / 64;
                }
        }

        spin_lock_irqsave(&dma_dom->domain.lock, flags);

        /* First take the bitmap_lock and then publish the range */
        spin_lock(&range->bitmap_lock);

        old_size                 = dma_dom->aperture_size;
        dma_dom->aperture[index] = range;
        dma_dom->aperture_size  += APERTURE_RANGE_SIZE;

        /* Reserve address range used for MSI messages */
        if (old_size < MSI_ADDR_BASE_LO &&
            dma_dom->aperture_size > MSI_ADDR_BASE_LO) {
                unsigned long spage;
                int pages;

                pages = iommu_num_pages(MSI_ADDR_BASE_LO, 0x10000, PAGE_SIZE);
                spage = MSI_ADDR_BASE_LO >> PAGE_SHIFT;

                dma_ops_reserve_addresses(dma_dom, spage, pages);
        }

        /* Initialize the exclusion range if necessary */
        for_each_iommu(iommu) {
                if (iommu->exclusion_start &&
                    iommu->exclusion_start >= dma_dom->aperture[index]->offset
                    && iommu->exclusion_start < dma_dom->aperture_size) {
                        unsigned long startpage;
                        int pages = iommu_num_pages(iommu->exclusion_start,
                                                    iommu->exclusion_length,
                                                    PAGE_SIZE);
                        startpage = iommu->exclusion_start >> PAGE_SHIFT;
                        dma_ops_reserve_addresses(dma_dom, startpage, pages);
                }
        }

        /*
         * Check for areas already mapped as present in the new aperture
         * range and mark those pages as reserved in the allocator. Such
         * mappings may already exist as a result of requested unity
         * mappings for devices.
         */
        for (i = dma_dom->aperture[index]->offset;
             i < dma_dom->aperture_size;
             i += pte_pgsize) {
                u64 *pte = fetch_pte(&dma_dom->domain, i, &pte_pgsize);
                if (!pte || !IOMMU_PTE_PRESENT(*pte))
                        continue;

                dma_ops_reserve_addresses(dma_dom, i >> PAGE_SHIFT,
                                          pte_pgsize >> 12);
        }

        update_domain(&dma_dom->domain);

        spin_unlock(&range->bitmap_lock);

        spin_unlock_irqrestore(&dma_dom->domain.lock, flags);

        return 0;

out_free:
        update_domain(&dma_dom->domain);

        free_page((unsigned long)range->bitmap);

        kfree(range);

        return -ENOMEM;
}

static dma_addr_t dma_ops_aperture_alloc(struct dma_ops_domain *dom,
                                         struct aperture_range *range,
                                         unsigned long pages,
                                         unsigned long dma_mask,
                                         unsigned long boundary_size,
                                         unsigned long align_mask,
                                         bool trylock)
{
        unsigned long offset, limit, flags;
        dma_addr_t address;
        bool flush = false;

        offset = range->offset >> PAGE_SHIFT;
        limit  = iommu_device_max_index(APERTURE_RANGE_PAGES, offset,
                                        dma_mask >> PAGE_SHIFT);

        if (trylock) {
                if (!spin_trylock_irqsave(&range->bitmap_lock, flags))
                        return -1;
        } else {
                spin_lock_irqsave(&range->bitmap_lock, flags);
        }

        address = iommu_area_alloc(range->bitmap, limit, range->next_bit,
                                   pages, offset, boundary_size, align_mask);
        if (address == -1) {
                /* Nothing found, retry one time */
                address = iommu_area_alloc(range->bitmap, limit,
                                           0, pages, offset, boundary_size,
                                           align_mask);
                flush = true;
        }

        if (address != -1)
                range->next_bit = address + pages;

        spin_unlock_irqrestore(&range->bitmap_lock, flags);

        if (flush) {
                domain_flush_tlb(&dom->domain);
                domain_flush_complete(&dom->domain);
        }

        return address;
}

static unsigned long dma_ops_area_alloc(struct device *dev,
                                        struct dma_ops_domain *dom,
                                        unsigned int pages,
                                        unsigned long align_mask,
                                        u64 dma_mask)
{
        unsigned long boundary_size, mask;
        unsigned long address = -1;
        bool first = true;
        u32 start, i;

        preempt_disable();

        mask = dma_get_seg_boundary(dev);

again:
        start = this_cpu_read(*dom->next_index);

        /* Sanity check - is it really necessary? */
        if (unlikely(start > APERTURE_MAX_RANGES)) {
                start = 0;
                this_cpu_write(*dom->next_index, 0);
        }

        boundary_size = mask + 1 ? ALIGN(mask + 1, PAGE_SIZE) >> PAGE_SHIFT :
                                   1UL << (BITS_PER_LONG - PAGE_SHIFT);

        for (i = 0; i < APERTURE_MAX_RANGES; ++i) {
                struct aperture_range *range;
                int index;

                index = (start + i) % APERTURE_MAX_RANGES;

                range = dom->aperture[index];

                if (!range || range->offset >= dma_mask)
                        continue;

                address = dma_ops_aperture_alloc(dom, range, pages,
                                                 dma_mask, boundary_size,
                                                 align_mask, first);
                if (address != -1) {
                        address = range->offset + (address << PAGE_SHIFT);
                        this_cpu_write(*dom->next_index, index);
                        break;
                }
        }

        if (address == -1 && first) {
                first = false;
                goto again;
        }

        preempt_enable();

        return address;
}

static unsigned long dma_ops_alloc_addresses(struct device *dev,
                                             struct dma_ops_domain *dom,
                                             unsigned int pages,
                                             unsigned long align_mask,
                                             u64 dma_mask)
{
        unsigned long address = -1;

        while (address == -1) {
                address = dma_ops_area_alloc(dev, dom, pages,
                                             align_mask, dma_mask);

                if (address == -1 && alloc_new_range(dom, false, GFP_ATOMIC))
                        break;
        }

        if (unlikely(address == -1))
                address = DMA_ERROR_CODE;

        WARN_ON((address + (PAGE_SIZE*pages)) > dom->aperture_size);

        return address;
}

/*
 * The address free function.
 *
 * called with domain->lock held
 */
static void dma_ops_free_addresses(struct dma_ops_domain *dom,
                                   unsigned long address,
                                   unsigned int pages)
{
        unsigned i = address >> APERTURE_RANGE_SHIFT;
        struct aperture_range *range = dom->aperture[i];
        unsigned long flags;

        BUG_ON(i >= APERTURE_MAX_RANGES || range == NULL);

#ifdef CONFIG_IOMMU_STRESS
        if (i < 4)
                return;
#endif

        if (amd_iommu_unmap_flush) {
                domain_flush_tlb(&dom->domain);
                domain_flush_complete(&dom->domain);
        }

        address = (address % APERTURE_RANGE_SIZE) >> PAGE_SHIFT;

        spin_lock_irqsave(&range->bitmap_lock, flags);
        if (address + pages > range->next_bit)
                range->next_bit = address + pages;
        bitmap_clear(range->bitmap, address, pages);
        spin_unlock_irqrestore(&range->bitmap_lock, flags);

}

/****************************************************************************
 *
 * The next functions belong to the domain allocation. A domain is
 * allocated for every IOMMU as the default domain. If device isolation
 * is enabled, every device get its own domain. The most important thing
 * about domains is the page table mapping the DMA address space they
 * contain.
 *
 ****************************************************************************/

/*
 * This function adds a protection domain to the global protection domain list
 */
static void add_domain_to_list(struct protection_domain *domain)
{
        unsigned long flags;

        spin_lock_irqsave(&amd_iommu_pd_lock, flags);
        list_add(&domain->list, &amd_iommu_pd_list);
        spin_unlock_irqrestore(&amd_iommu_pd_lock, flags);
}

/*
 * This function removes a protection domain to the global
 * protection domain list
 */
static void del_domain_from_list(struct protection_domain *domain)
{
        unsigned long flags;

        spin_lock_irqsave(&amd_iommu_pd_lock, flags);
        list_del(&domain->list);
        spin_unlock_irqrestore(&amd_iommu_pd_lock, flags);
}

static u16 domain_id_alloc(void)
{
        unsigned long flags;
        int id;

        write_lock_irqsave(&amd_iommu_devtable_lock, flags);
        id = find_first_zero_bit(amd_iommu_pd_alloc_bitmap, MAX_DOMAIN_ID);
        BUG_ON(id == 0);
        if (id > 0 && id < MAX_DOMAIN_ID)
                __set_bit(id, amd_iommu_pd_alloc_bitmap);
        else
                id = 0;
        write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);

        return id;
}

static void domain_id_free(int id)
{
        unsigned long flags;

        write_lock_irqsave(&amd_iommu_devtable_lock, flags);
        if (id > 0 && id < MAX_DOMAIN_ID)
                __clear_bit(id, amd_iommu_pd_alloc_bitmap);
        write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
}

#define DEFINE_FREE_PT_FN(LVL, FN)                              \
static void free_pt_##LVL (unsigned long __pt)                  \
{                                                               \
        unsigned long p;                                        \
        u64 *pt;                                                \
        int i;                                                  \
                                                                \
        pt = (u64 *)__pt;                                       \
                                                                \
        for (i = 0; i < 512; ++i) {                             \
                /* PTE present? */                              \
                if (!IOMMU_PTE_PRESENT(pt[i]))                  \
                        continue;                               \
                                                                \
                /* Large PTE? */                                \
                if (PM_PTE_LEVEL(pt[i]) == 0 ||                 \
                    PM_PTE_LEVEL(pt[i]) == 7)                   \
                        continue;                               \
                                                                \
                p = (unsigned long)IOMMU_PTE_PAGE(pt[i]);       \
                FN(p);                                          \
        }                                                       \
        free_page((unsigned long)pt);                           \
}

DEFINE_FREE_PT_FN(l2, free_page)
DEFINE_FREE_PT_FN(l3, free_pt_l2)
DEFINE_FREE_PT_FN(l4, free_pt_l3)
DEFINE_FREE_PT_FN(l5, free_pt_l4)
DEFINE_FREE_PT_FN(l6, free_pt_l5)

static void free_pagetable(struct protection_domain *domain)
{
        unsigned long root = (unsigned long)domain->pt_root;

        switch (domain->mode) {
        case PAGE_MODE_NONE:
                break;
        case PAGE_MODE_1_LEVEL:
                free_page(root);
                break;
        case PAGE_MODE_2_LEVEL:
                free_pt_l2(root);
                break;
        case PAGE_MODE_3_LEVEL:
                free_pt_l3(root);
                break;
        case PAGE_MODE_4_LEVEL:
                free_pt_l4(root);
                break;
        case PAGE_MODE_5_LEVEL:
                free_pt_l5(root);
                break;
        case PAGE_MODE_6_LEVEL:
                free_pt_l6(root);
                break;
        default:
                BUG();
        }
}

static void free_gcr3_tbl_level1(u64 *tbl)
{
        u64 *ptr;
        int i;

        for (i = 0; i < 512; ++i) {
                if (!(tbl[i] & GCR3_VALID))
                        continue;

                ptr = __va(tbl[i] & PAGE_MASK);

                free_page((unsigned long)ptr);
        }
}

static void free_gcr3_tbl_level2(u64 *tbl)
{
        u64 *ptr;
        int i;

        for (i = 0; i < 512; ++i) {
                if (!(tbl[i] & GCR3_VALID))
                        continue;

                ptr = __va(tbl[i] & PAGE_MASK);

                free_gcr3_tbl_level1(ptr);
        }
}

static void free_gcr3_table(struct protection_domain *domain)
{
        if (domain->glx == 2)
                free_gcr3_tbl_level2(domain->gcr3_tbl);
        else if (domain->glx == 1)
                free_gcr3_tbl_level1(domain->gcr3_tbl);
        else
                BUG_ON(domain->glx != 0);

        free_page((unsigned long)domain->gcr3_tbl);
}

/*
 * Free a domain, only used if something went wrong in the
 * allocation path and we need to free an already allocated page table
 */
static void dma_ops_domain_free(struct dma_ops_domain *dom)
{
        int i;

        if (!dom)
                return;

        free_percpu(dom->next_index);

        del_domain_from_list(&dom->domain);

        free_pagetable(&dom->domain);

        for (i = 0; i < APERTURE_MAX_RANGES; ++i) {
                if (!dom->aperture[i])
                        continue;
                free_page((unsigned long)dom->aperture[i]->bitmap);
                kfree(dom->aperture[i]);
        }

        kfree(dom);
}

static int dma_ops_domain_alloc_apertures(struct dma_ops_domain *dma_dom,
                                          int max_apertures)
{
        int ret, i, apertures;

        apertures = dma_dom->aperture_size >> APERTURE_RANGE_SHIFT;
        ret       = 0;

        for (i = apertures; i < max_apertures; ++i) {
                ret = alloc_new_range(dma_dom, false, GFP_KERNEL);
                if (ret)
                        break;
        }

        return ret;
}

/*
 * Allocates a new protection domain usable for the dma_ops functions.
 * It also initializes the page table and the address allocator data
 * structures required for the dma_ops interface
 */
static struct dma_ops_domain *dma_ops_domain_alloc(void)
{
        struct dma_ops_domain *dma_dom;
        int cpu;

        dma_dom = kzalloc(sizeof(struct dma_ops_domain), GFP_KERNEL);
        if (!dma_dom)
                return NULL;

        if (protection_domain_init(&dma_dom->domain))
                goto free_dma_dom;

        dma_dom->next_index = alloc_percpu(u32);
        if (!dma_dom->next_index)
                goto free_dma_dom;

        dma_dom->domain.mode = PAGE_MODE_2_LEVEL;
        dma_dom->domain.pt_root = (void *)get_zeroed_page(GFP_KERNEL);
        dma_dom->domain.flags = PD_DMA_OPS_MASK;
        dma_dom->domain.priv = dma_dom;
        if (!dma_dom->domain.pt_root)
                goto free_dma_dom;

        add_domain_to_list(&dma_dom->domain);

        if (alloc_new_range(dma_dom, true, GFP_KERNEL))
                goto free_dma_dom;

        /*
         * mark the first page as allocated so we never return 0 as
         * a valid dma-address. So we can use 0 as error value
         */
        dma_dom->aperture[0]->bitmap[0] = 1;

        for_each_possible_cpu(cpu)
                *per_cpu_ptr(dma_dom->next_index, cpu) = 0;

        return dma_dom;

free_dma_dom:
        dma_ops_domain_free(dma_dom);

        return NULL;
}

/*
 * little helper function to check whether a given protection domain is a
 * dma_ops domain
 */
static bool dma_ops_domain(struct protection_domain *domain)
{
        return domain->flags & PD_DMA_OPS_MASK;
}

static void set_dte_entry(u16 devid, struct protection_domain *domain, bool ats)
{
        u64 pte_root = 0;
        u64 flags = 0;

        if (domain->mode != PAGE_MODE_NONE)
                pte_root = virt_to_phys(domain->pt_root);

        pte_root |= (domain->mode & DEV_ENTRY_MODE_MASK)
                    << DEV_ENTRY_MODE_SHIFT;
        pte_root |= IOMMU_PTE_IR | IOMMU_PTE_IW | IOMMU_PTE_P | IOMMU_PTE_TV;

        flags = amd_iommu_dev_table[devid].data[1];

        if (ats)
                flags |= DTE_FLAG_IOTLB;

        if (domain->flags & PD_IOMMUV2_MASK) {
                u64 gcr3 = __pa(domain->gcr3_tbl);
                u64 glx  = domain->glx;
                u64 tmp;

                pte_root |= DTE_FLAG_GV;
                pte_root |= (glx & DTE_GLX_MASK) << DTE_GLX_SHIFT;

                /* First mask out possible old values for GCR3 table */
                tmp = DTE_GCR3_VAL_B(~0ULL) << DTE_GCR3_SHIFT_B;
                flags    &= ~tmp;

                tmp = DTE_GCR3_VAL_C(~0ULL) << DTE_GCR3_SHIFT_C;
                flags    &= ~tmp;

                /* Encode GCR3 table into DTE */
                tmp = DTE_GCR3_VAL_A(gcr3) << DTE_GCR3_SHIFT_A;
                pte_root |= tmp;

                tmp = DTE_GCR3_VAL_B(gcr3) << DTE_GCR3_SHIFT_B;
                flags    |= tmp;

                tmp = DTE_GCR3_VAL_C(gcr3) << DTE_GCR3_SHIFT_C;
                flags    |= tmp;
        }

        flags &= ~(0xffffUL);
        flags |= domain->id;

        amd_iommu_dev_table[devid].data[1]  = flags;
        amd_iommu_dev_table[devid].data[0]  = pte_root;
}

static void clear_dte_entry(u16 devid)
{
        /* remove entry from the device table seen by the hardware */
        amd_iommu_dev_table[devid].data[0]  = IOMMU_PTE_P | IOMMU_PTE_TV;
        amd_iommu_dev_table[devid].data[1] &= DTE_FLAG_MASK;

        amd_iommu_apply_erratum_63(devid);
}

static void do_attach(struct iommu_dev_data *dev_data,
                      struct protection_domain *domain)
{
        struct amd_iommu *iommu;
        u16 alias;
        bool ats;

        iommu = amd_iommu_rlookup_table[dev_data->devid];
        alias = dev_data->alias;
        ats   = dev_data->ats.enabled;

        /* Update data structures */
        dev_data->domain = domain;
        list_add(&dev_data->list, &domain->dev_list);

        /* Do reference counting */
        domain->dev_iommu[iommu->index] += 1;
        domain->dev_cnt                 += 1;

        /* Update device table */
        set_dte_entry(dev_data->devid, domain, ats);
        if (alias != dev_data->devid)
                set_dte_entry(alias, domain, ats);

        device_flush_dte(dev_data);
}

static void do_detach(struct iommu_dev_data *dev_data)
{
        struct amd_iommu *iommu;
        u16 alias;

        /*
         * First check if the device is still attached. It might already
         * be detached from its domain because the generic
         * iommu_detach_group code detached it and we try again here in
         * our alias handling.
         */
        if (!dev_data->domain)
                return;

        iommu = amd_iommu_rlookup_table[dev_data->devid];
        alias = dev_data->alias;

        /* decrease reference counters */
        dev_data->domain->dev_iommu[iommu->index] -= 1;
        dev_data->domain->dev_cnt                 -= 1;

        /* Update data structures */
        dev_data->domain = NULL;
        list_del(&dev_data->list);
        clear_dte_entry(dev_data->devid);
        if (alias != dev_data->devid)
                clear_dte_entry(alias);

        /* Flush the DTE entry */
        device_flush_dte(dev_data);
}

/*
 * If a device is not yet associated with a domain, this function does
 * assigns it visible for the hardware
 */
static int __attach_device(struct iommu_dev_data *dev_data,
                           struct protection_domain *domain)
{
        int ret;

        /*
         * Must be called with IRQs disabled. Warn here to detect early
         * when its not.
         */
        WARN_ON(!irqs_disabled());

        /* lock domain */
        spin_lock(&domain->lock);

        ret = -EBUSY;
        if (dev_data->domain != NULL)
                goto out_unlock;

        /* Attach alias group root */
        do_attach(dev_data, domain);

        ret = 0;

out_unlock:

        /* ready */
        spin_unlock(&domain->lock);

        return ret;
}


static void pdev_iommuv2_disable(struct pci_dev *pdev)
{
        pci_disable_ats(pdev);
        pci_disable_pri(pdev);
        pci_disable_pasid(pdev);
}

/* FIXME: Change generic reset-function to do the same */
static int pri_reset_while_enabled(struct pci_dev *pdev)
{
        u16 control;
        int pos;

        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
        if (!pos)
                return -EINVAL;

        pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
        control |= PCI_PRI_CTRL_RESET;
        pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);

        return 0;
}

static int pdev_iommuv2_enable(struct pci_dev *pdev)
{
        bool reset_enable;
        int reqs, ret;

        /* FIXME: Hardcode number of outstanding requests for now */
        reqs = 32;
        if (pdev_pri_erratum(pdev, AMD_PRI_DEV_ERRATUM_LIMIT_REQ_ONE))
                reqs = 1;
        reset_enable = pdev_pri_erratum(pdev, AMD_PRI_DEV_ERRATUM_ENABLE_RESET);

        /* Only allow access to user-accessible pages */
        ret = pci_enable_pasid(pdev, 0);
        if (ret)
                goto out_err;

        /* First reset the PRI state of the device */
        ret = pci_reset_pri(pdev);
        if (ret)
                goto out_err;

        /* Enable PRI */
        ret = pci_enable_pri(pdev, reqs);
        if (ret)
                goto out_err;

        if (reset_enable) {
                ret = pri_reset_while_enabled(pdev);
                if (ret)
                        goto out_err;
        }

        ret = pci_enable_ats(pdev, PAGE_SHIFT);
        if (ret)
                goto out_err;

        return 0;

out_err:
        pci_disable_pri(pdev);
        pci_disable_pasid(pdev);

        return ret;
}

/* FIXME: Move this to PCI code */
#define PCI_PRI_TLP_OFF         (1 << 15)

static bool pci_pri_tlp_required(struct pci_dev *pdev)
{
        u16 status;
        int pos;

        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
        if (!pos)
                return false;

        pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);

        return (status & PCI_PRI_TLP_OFF) ? true : false;
}

/*
 * If a device is not yet associated with a domain, this function
 * assigns it visible for the hardware
 */
static int attach_device(struct device *dev,
                         struct protection_domain *domain)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct iommu_dev_data *dev_data;
        unsigned long flags;
        int ret;

        dev_data = get_dev_data(dev);

        if (domain->flags & PD_IOMMUV2_MASK) {
                if (!dev_data->passthrough)
                        return -EINVAL;

                if (dev_data->iommu_v2) {
                        if (pdev_iommuv2_enable(pdev) != 0)
                                return -EINVAL;

                        dev_data->ats.enabled = true;
                        dev_data->ats.qdep    = pci_ats_queue_depth(pdev);
                        dev_data->pri_tlp     = pci_pri_tlp_required(pdev);
                }
        } else if (amd_iommu_iotlb_sup &&
                   pci_enable_ats(pdev, PAGE_SHIFT) == 0) {
                dev_data->ats.enabled = true;
                dev_data->ats.qdep    = pci_ats_queue_depth(pdev);
        }

        write_lock_irqsave(&amd_iommu_devtable_lock, flags);
        ret = __attach_device(dev_data, domain);
        write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);

        /*
         * We might boot into a crash-kernel here. The crashed kernel
         * left the caches in the IOMMU dirty. So we have to flush
         * here to evict all dirty stuff.
         */
        domain_flush_tlb_pde(domain);

        return ret;
}

/*
 * Removes a device from a protection domain (unlocked)
 */
static void __detach_device(struct iommu_dev_data *dev_data)
{
        struct protection_domain *domain;

        /*
         * Must be called with IRQs disabled. Warn here to detect early
         * when its not.
         */
        WARN_ON(!irqs_disabled());

        if (WARN_ON(!dev_data->domain))
                return;

        domain = dev_data->domain;

        spin_lock(&domain->lock);

        do_detach(dev_data);

        spin_unlock(&domain->lock);
}

/*
 * Removes a device from a protection domain (with devtable_lock held)
 */
static void detach_device(struct device *dev)
{
        struct protection_domain *domain;
        struct iommu_dev_data *dev_data;
        unsigned long flags;

        dev_data = get_dev_data(dev);
        domain   = dev_data->domain;

        /* lock device table */
        write_lock_irqsave(&amd_iommu_devtable_lock, flags);
        __detach_device(dev_data);
        write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);

        if (domain->flags & PD_IOMMUV2_MASK && dev_data->iommu_v2)
                pdev_iommuv2_disable(to_pci_dev(dev));
        else if (dev_data->ats.enabled)
                pci_disable_ats(to_pci_dev(dev));

        dev_data->ats.enabled = false;
}

static int amd_iommu_add_device(struct device *dev)
{
        struct iommu_dev_data *dev_data;
        struct iommu_domain *domain;
        struct amd_iommu *iommu;
        u16 devid;
        int ret;

        if (!check_device(dev) || get_dev_data(dev))
                return 0;

        devid = get_device_id(dev);
        iommu = amd_iommu_rlookup_table[devid];

        ret = iommu_init_device(dev);
        if (ret) {
                if (ret != -ENOTSUPP)
                        pr_err("Failed to initialize device %s - trying to proceed anyway\n",
                                dev_name(dev));

                iommu_ignore_device(dev);
                dev->archdata.dma_ops = &nommu_dma_ops;
                goto out;
        }
        init_iommu_group(dev);

        dev_data = get_dev_data(dev);

        BUG_ON(!dev_data);

        if (iommu_pass_through || dev_data->iommu_v2)
                iommu_request_dm_for_dev(dev);

        /* Domains are initialized for this device - have a look what we ended up with */
        domain = iommu_get_domain_for_dev(dev);
        if (domain->type == IOMMU_DOMAIN_IDENTITY)
                dev_data->passthrough = true;
        else
                dev->archdata.dma_ops = &amd_iommu_dma_ops;

out:
        iommu_completion_wait(iommu);

        return 0;
}

static void amd_iommu_remove_device(struct device *dev)
{
        struct amd_iommu *iommu;
        u16 devid;

        if (!check_device(dev))
                return;

        devid = get_device_id(dev);
        iommu = amd_iommu_rlookup_table[devid];

        iommu_uninit_device(dev);
        iommu_completion_wait(iommu);
}

/*****************************************************************************
 *
 * The next functions belong to the dma_ops mapping/unmapping code.
 *
 *****************************************************************************/

/*
 * In the dma_ops path we only have the struct device. This function
 * finds the corresponding IOMMU, the protection domain and the
 * requestor id for a given device.
 * If the device is not yet associated with a domain this is also done
 * in this function.
 */
static struct protection_domain *get_domain(struct device *dev)
{
        struct protection_domain *domain;
        struct iommu_domain *io_domain;

        if (!check_device(dev))
                return ERR_PTR(-EINVAL);

        io_domain = iommu_get_domain_for_dev(dev);
        if (!io_domain)
                return NULL;

        domain = to_pdomain(io_domain);
        if (!dma_ops_domain(domain))
                return ERR_PTR(-EBUSY);

        return domain;
}

static void update_device_table(struct protection_domain *domain)
{
        struct iommu_dev_data *dev_data;

        list_for_each_entry(dev_data, &domain->dev_list, list)
                set_dte_entry(dev_data->devid, domain, dev_data->ats.enabled);
}

static void update_domain(struct protection_domain *domain)
{
        if (!domain->updated)
                return;

        update_device_table(domain);

        domain_flush_devices(domain);
        domain_flush_tlb_pde(domain);

        domain->updated = false;
}

/*
 * This function fetches the PTE for a given address in the aperture
 */
static u64* dma_ops_get_pte(struct dma_ops_domain *dom,
                            unsigned long address)
{
        struct aperture_range *aperture;
        u64 *pte, *pte_page;

        aperture = dom->aperture[APERTURE_RANGE_INDEX(address)];
        if (!aperture)
                return NULL;

        pte = aperture->pte_pages[APERTURE_PAGE_INDEX(address)];
        if (!pte) {
                pte = alloc_pte(&dom->domain, address, PAGE_SIZE, &pte_page,
                                GFP_ATOMIC);
                aperture->pte_pages[APERTURE_PAGE_INDEX(address)] = pte_page;
        } else
                pte += PM_LEVEL_INDEX(0, address);

        update_domain(&dom->domain);

        return pte;
}

/*
 * This is the generic map function. It maps one 4kb page at paddr to
 * the given address in the DMA address space for the domain.
 */
static dma_addr_t dma_ops_domain_map(struct dma_ops_domain *dom,
                                     unsigned long address,
                                     phys_addr_t paddr,
                                     int direction)
{
        u64 *pte, __pte;

        WARN_ON(address > dom->aperture_size);

        paddr &= PAGE_MASK;

        pte  = dma_ops_get_pte(dom, address);
        if (!pte)
                return DMA_ERROR_CODE;

        __pte = paddr | IOMMU_PTE_P | IOMMU_PTE_FC;

        if (direction == DMA_TO_DEVICE)
                __pte |= IOMMU_PTE_IR;
        else if (direction == DMA_FROM_DEVICE)
                __pte |= IOMMU_PTE_IW;
        else if (direction == DMA_BIDIRECTIONAL)
                __pte |= IOMMU_PTE_IR | IOMMU_PTE_IW;

        WARN_ON_ONCE(*pte);

        *pte = __pte;

        return (dma_addr_t)address;
}

/*
 * The generic unmapping function for on page in the DMA address space.
 */
static void dma_ops_domain_unmap(struct dma_ops_domain *dom,
                                 unsigned long address)
{
        struct aperture_range *aperture;
        u64 *pte;

        if (address >= dom->aperture_size)
                return;

        aperture = dom->aperture[APERTURE_RANGE_INDEX(address)];
        if (!aperture)
                return;

        pte  = aperture->pte_pages[APERTURE_PAGE_INDEX(address)];
        if (!pte)
                return;

        pte += PM_LEVEL_INDEX(0, address);

        WARN_ON_ONCE(!*pte);

        *pte = 0ULL;
}

/*
 * This function contains common code for mapping of a physically
 * contiguous memory region into DMA address space. It is used by all
 * mapping functions provided with this IOMMU driver.
 * Must be called with the domain lock held.
 */
static dma_addr_t __map_single(struct device *dev,
                               struct dma_ops_domain *dma_dom,
                               phys_addr_t paddr,
                               size_t size,
                               int dir,
                               bool align,
                               u64 dma_mask)
{
        dma_addr_t offset = paddr & ~PAGE_MASK;
        dma_addr_t address, start, ret;
        unsigned int pages;
        unsigned long align_mask = 0;
        int i;

        pages = iommu_num_pages(paddr, size, PAGE_SIZE);
        paddr &= PAGE_MASK;

        INC_STATS_COUNTER(total_map_requests);

        if (pages > 1)
                INC_STATS_COUNTER(cross_page);

        if (align)
                align_mask = (1UL << get_order(size)) - 1;

        address = dma_ops_alloc_addresses(dev, dma_dom, pages, align_mask,
                                          dma_mask);

        if (address == DMA_ERROR_CODE)
                goto out;

        start = address;
        for (i = 0; i < pages; ++i) {
                ret = dma_ops_domain_map(dma_dom, start, paddr, dir);
                if (ret == DMA_ERROR_CODE)
                        goto out_unmap;

                paddr += PAGE_SIZE;
                start += PAGE_SIZE;
        }
        address += offset;

        ADD_STATS_COUNTER(alloced_io_mem, size);

        if (unlikely(amd_iommu_np_cache)) {
                domain_flush_pages(&dma_dom->domain, address, size);
                domain_flush_complete(&dma_dom->domain);
        }

out:
        return address;

out_unmap:

        for (--i; i >= 0; --i) {
                start -= PAGE_SIZE;
                dma_ops_domain_unmap(dma_dom, start);
        }

        dma_ops_free_addresses(dma_dom, address, pages);

        return DMA_ERROR_CODE;
}

/*
 * Does the reverse of the __map_single function. Must be called with
 * the domain lock held too
 */
static void __unmap_single(struct dma_ops_domain *dma_dom,
                           dma_addr_t dma_addr,
                           size_t size,
                           int dir)
{
        dma_addr_t flush_addr;
        dma_addr_t i, start;
        unsigned int pages;

        if ((dma_addr == DMA_ERROR_CODE) ||
            (dma_addr + size > dma_dom->aperture_size))
                return;

        flush_addr = dma_addr;
        pages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
        dma_addr &= PAGE_MASK;
        start = dma_addr;

        for (i = 0; i < pages; ++i) {
                dma_ops_domain_unmap(dma_dom, start);
                start += PAGE_SIZE;
        }

        SUB_STATS_COUNTER(alloced_io_mem, size);

        dma_ops_free_addresses(dma_dom, dma_addr, pages);
}

/*
 * The exported map_single function for dma_ops.
 */
static dma_addr_t map_page(struct device *dev, struct page *page,
                           unsigned long offset, size_t size,
                           enum dma_data_direction dir,
                           struct dma_attrs *attrs)
{
        phys_addr_t paddr = page_to_phys(page) + offset;
        struct protection_domain *domain;
        u64 dma_mask;

        INC_STATS_COUNTER(cnt_map_single);

        domain = get_domain(dev);
        if (PTR_ERR(domain) == -EINVAL)
                return (dma_addr_t)paddr;
        else if (IS_ERR(domain))
                return DMA_ERROR_CODE;

        dma_mask = *dev->dma_mask;

        return __map_single(dev, domain->priv, paddr, size, dir, false,
                            dma_mask);
}

/*
 * The exported unmap_single function for dma_ops.
 */
static void unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
                       enum dma_data_direction dir, struct dma_attrs *attrs)
{
        struct protection_domain *domain;

        INC_STATS_COUNTER(cnt_unmap_single);

        domain = get_domain(dev);
        if (IS_ERR(domain))
                return;

        __unmap_single(domain->priv, dma_addr, size, dir);
}

/*
 * The exported map_sg function for dma_ops (handles scatter-gather
 * lists).
 */
static int map_sg(struct device *dev, struct scatterlist *sglist,
                  int nelems, enum dma_data_direction dir,
                  struct dma_attrs *attrs)
{
        struct protection_domain *domain;
        int i;
        struct scatterlist *s;
        phys_addr_t paddr;
        int mapped_elems = 0;
        u64 dma_mask;

        INC_STATS_COUNTER(cnt_map_sg);

        domain = get_domain(dev);
        if (IS_ERR(domain))
                return 0;

        dma_mask = *dev->dma_mask;

        for_each_sg(sglist, s, nelems, i) {
                paddr = sg_phys(s);

                s->dma_address = __map_single(dev, domain->priv,
                                              paddr, s->length, dir, false,
                                              dma_mask);

                if (s->dma_address) {
                        s->dma_length = s->length;
                        mapped_elems++;
                } else
                        goto unmap;
        }

        return mapped_elems;

unmap:
        for_each_sg(sglist, s, mapped_elems, i) {
                if (s->dma_address)
                        __unmap_single(domain->priv, s->dma_address,
                                       s->dma_length, dir);
                s->dma_address = s->dma_length = 0;
        }

        return 0;
}

/*
 * The exported map_sg function for dma_ops (handles scatter-gather
 * lists).
 */
static void unmap_sg(struct device *dev, struct scatterlist *sglist,
                     int nelems, enum dma_data_direction dir,
                     struct dma_attrs *attrs)
{
        struct protection_domain *domain;
        struct scatterlist *s;
        int i;

        INC_STATS_COUNTER(cnt_unmap_sg);

        domain = get_domain(dev);
        if (IS_ERR(domain))
                return;

        for_each_sg(sglist, s, nelems, i) {
                __unmap_single(domain->priv, s->dma_address,
                               s->dma_length, dir);
                s->dma_address = s->dma_length = 0;
        }
}

/*
 * The exported alloc_coherent function for dma_ops.
 */
static void *alloc_coherent(struct device *dev, size_t size,
                            dma_addr_t *dma_addr, gfp_t flag,
                            struct dma_attrs *attrs)
{
        u64 dma_mask = dev->coherent_dma_mask;
        struct protection_domain *domain;
        struct page *page;

        INC_STATS_COUNTER(cnt_alloc_coherent);

        domain = get_domain(dev);
        if (PTR_ERR(domain) == -EINVAL) {
                page = alloc_pages(flag, get_order(size));
                *dma_addr = page_to_phys(page);
                return page_address(page);
        } else if (IS_ERR(domain))
                return NULL;

        size      = PAGE_ALIGN(size);
        dma_mask  = dev->coherent_dma_mask;
        flag     &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
        flag     |= __GFP_ZERO;

        page = alloc_pages(flag | __GFP_NOWARN,  get_order(size));
        if (!page) {
                if (!gfpflags_allow_blocking(flag))
                        return NULL;

                page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
                                                 get_order(size));
                if (!page)
                        return NULL;
        }

        if (!dma_mask)
                dma_mask = *dev->dma_mask;

        *dma_addr = __map_single(dev, domain->priv, page_to_phys(page),
                                 size, DMA_BIDIRECTIONAL, true, dma_mask);

        if (*dma_addr == DMA_ERROR_CODE)
                goto out_free;

        return page_address(page);

out_free:

        if (!dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT))
                __free_pages(page, get_order(size));

        return NULL;
}

/*
 * The exported free_coherent function for dma_ops.
 */
static void free_coherent(struct device *dev, size_t size,
                          void *virt_addr, dma_addr_t dma_addr,
                          struct dma_attrs *attrs)
{
        struct protection_domain *domain;
        struct page *page;

        INC_STATS_COUNTER(cnt_free_coherent);

        page = virt_to_page(virt_addr);
        size = PAGE_ALIGN(size);

        domain = get_domain(dev);
        if (IS_ERR(domain))
                goto free_mem;

        __unmap_single(domain->priv, dma_addr, size, DMA_BIDIRECTIONAL);

free_mem:
        if (!dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT))
                __free_pages(page, get_order(size));
}

/*
 * This function is called by the DMA layer to find out if we can handle a
 * particular device. It is part of the dma_ops.
 */
static int amd_iommu_dma_supported(struct device *dev, u64 mask)
{
        return check_device(dev);
}

static int set_dma_mask(struct device *dev, u64 mask)
{
        struct protection_domain *domain;
        int max_apertures = 1;

        domain = get_domain(dev);
        if (IS_ERR(domain))
                return PTR_ERR(domain);

        if (mask == DMA_BIT_MASK(64))
                max_apertures = 8;
        else if (mask > DMA_BIT_MASK(32))
                max_apertures = 4;

        /*
         * To prevent lock contention it doesn't make sense to allocate more
         * apertures than online cpus
         */
        if (max_apertures > num_online_cpus())
                max_apertures = num_online_cpus();

        if (dma_ops_domain_alloc_apertures(domain->priv, max_apertures))
                dev_err(dev, "Can't allocate %d iommu apertures\n",
                        max_apertures);

        return 0;
}

static struct dma_map_ops amd_iommu_dma_ops = {
        .alloc          = alloc_coherent,
        .free           = free_coherent,
        .map_page       = map_page,
        .unmap_page     = unmap_page,
        .map_sg         = map_sg,
        .unmap_sg       = unmap_sg,
        .dma_supported  = amd_iommu_dma_supported,
        .set_dma_mask   = set_dma_mask,
};

int __init amd_iommu_init_api(void)
{
        return bus_set_iommu(&pci_bus_type, &amd_iommu_ops);
}

int __init amd_iommu_init_dma_ops(void)
{
        swiotlb        = iommu_pass_through ? 1 : 0;
        iommu_detected = 1;

        /*
         * In case we don't initialize SWIOTLB (actually the common case
         * when AMD IOMMU is enabled), make sure there are global
         * dma_ops set as a fall-back for devices not handled by this
         * driver (for example non-PCI devices).
         */
        if (!swiotlb)
                dma_ops = &nommu_dma_ops;

        amd_iommu_stats_init();

        if (amd_iommu_unmap_flush)
                pr_info("AMD-Vi: IO/TLB flush on unmap enabled\n");
        else
                pr_info("AMD-Vi: Lazy IO/TLB flushing enabled\n");

        return 0;
}

/*****************************************************************************
 *
 * The following functions belong to the exported interface of AMD IOMMU
 *
 * This interface allows access to lower level functions of the IOMMU
 * like protection domain handling and assignement of devices to domains
 * which is not possible with the dma_ops interface.
 *
 *****************************************************************************/

static void cleanup_domain(struct protection_domain *domain)
{
        struct iommu_dev_data *entry;
        unsigned long flags;

        write_lock_irqsave(&amd_iommu_devtable_lock, flags);

        while (!list_empty(&domain->dev_list)) {
                entry = list_first_entry(&domain->dev_list,
                                         struct iommu_dev_data, list);
                __detach_device(entry);
        }

        write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
}

static void protection_domain_free(struct protection_domain *domain)
{
        if (!domain)
                return;

        del_domain_from_list(domain);

        if (domain->id)
                domain_id_free(domain->id);

        kfree(domain);
}

static int protection_domain_init(struct protection_domain *domain)
{
        spin_lock_init(&domain->lock);
        mutex_init(&domain->api_lock);
        domain->id = domain_id_alloc();

        if (!domain->id)
                return -ENOMEM;
        INIT_LIST_HEAD(&domain->dev_list);

        return 0;
}

static struct protection_domain *protection_domain_alloc(void)
{
        struct protection_domain *domain;

        domain = kzalloc(sizeof(*domain), GFP_KERNEL);
        if (!domain)
                return NULL;

        if (protection_domain_init(domain))
                goto out_err;

        add_domain_to_list(domain);

        return domain;

out_err:
        kfree(domain);

        return NULL;
}

static struct iommu_domain *amd_iommu_domain_alloc(unsigned type)
{
        struct protection_domain *pdomain;
        struct dma_ops_domain *dma_domain;

        switch (type) {
        case IOMMU_DOMAIN_UNMANAGED:
                pdomain = protection_domain_alloc();
                if (!pdomain)
                        return NULL;

                pdomain->mode    = PAGE_MODE_3_LEVEL;
                pdomain->pt_root = (void *)get_zeroed_page(GFP_KERNEL);
                if (!pdomain->pt_root) {
                        protection_domain_free(pdomain);
                        return NULL;
                }

                pdomain->domain.geometry.aperture_start = 0;
                pdomain->domain.geometry.aperture_end   = ~0ULL;
                pdomain->domain.geometry.force_aperture = true;

                break;
        case IOMMU_DOMAIN_DMA:
                dma_domain = dma_ops_domain_alloc();
                if (!dma_domain) {
                        pr_err("AMD-Vi: Failed to allocate\n");
                        return NULL;
                }
                pdomain = &dma_domain->domain;
                break;
        case IOMMU_DOMAIN_IDENTITY:
                pdomain = protection_domain_alloc();
                if (!pdomain)
                        return NULL;

                pdomain->mode = PAGE_MODE_NONE;
                break;
        default:
                return NULL;
        }

        return &pdomain->domain;
}

static void amd_iommu_domain_free(struct iommu_domain *dom)
{
        struct protection_domain *domain;

        if (!dom)
                return;

        domain = to_pdomain(dom);

        if (domain->dev_cnt > 0)
                cleanup_domain(domain);

        BUG_ON(domain->dev_cnt != 0);

        if (domain->mode != PAGE_MODE_NONE)
                free_pagetable(domain);

        if (domain->flags & PD_IOMMUV2_MASK)
                free_gcr3_table(domain);

        protection_domain_free(domain);
}

static void amd_iommu_detach_device(struct iommu_domain *dom,
                                    struct device *dev)
{
        struct iommu_dev_data *dev_data = dev->archdata.iommu;
        struct amd_iommu *iommu;
        u16 devid;

        if (!check_device(dev))
                return;

        devid = get_device_id(dev);

        if (dev_data->domain != NULL)
                detach_device(dev);

        iommu = amd_iommu_rlookup_table[devid];
        if (!iommu)
                return;

        iommu_completion_wait(iommu);
}

static int amd_iommu_attach_device(struct iommu_domain *dom,
                                   struct device *dev)
{
        struct protection_domain *domain = to_pdomain(dom);
        struct iommu_dev_data *dev_data;
        struct amd_iommu *iommu;
        int ret;

        if (!check_device(dev))
                return -EINVAL;

        dev_data = dev->archdata.iommu;

        iommu = amd_iommu_rlookup_table[dev_data->devid];
        if (!iommu)
                return -EINVAL;

        if (dev_data->domain)
                detach_device(dev);

        ret = attach_device(dev, domain);

        iommu_completion_wait(iommu);

        return ret;
}

static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova,
                         phys_addr_t paddr, size_t page_size, int iommu_prot)
{
        struct protection_domain *domain = to_pdomain(dom);
        int prot = 0;
        int ret;

        if (domain->mode == PAGE_MODE_NONE)
                return -EINVAL;

        if (iommu_prot & IOMMU_READ)
                prot |= IOMMU_PROT_IR;
        if (iommu_prot & IOMMU_WRITE)
                prot |= IOMMU_PROT_IW;

        mutex_lock(&domain->api_lock);
        ret = iommu_map_page(domain, iova, paddr, prot, page_size);
        mutex_unlock(&domain->api_lock);

        return ret;
}

static size_t amd_iommu_unmap(struct iommu_domain *dom, unsigned long iova,
                           size_t page_size)
{
        struct protection_domain *domain = to_pdomain(dom);
        size_t unmap_size;

        if (domain->mode == PAGE_MODE_NONE)
                return -EINVAL;

        mutex_lock(&domain->api_lock);
        unmap_size = iommu_unmap_page(domain, iova, page_size);
        mutex_unlock(&domain->api_lock);

        domain_flush_tlb_pde(domain);

        return unmap_size;
}

static phys_addr_t amd_iommu_iova_to_phys(struct iommu_domain *dom,
                                          dma_addr_t iova)
{
        struct protection_domain *domain = to_pdomain(dom);
        unsigned long offset_mask, pte_pgsize;
        u64 *pte, __pte;

        if (domain->mode == PAGE_MODE_NONE)
                return iova;

        pte = fetch_pte(domain, iova, &pte_pgsize);

        if (!pte || !IOMMU_PTE_PRESENT(*pte))
                return 0;

        offset_mask = pte_pgsize - 1;
        __pte       = *pte & PM_ADDR_MASK;

        return (__pte & ~offset_mask) | (iova & offset_mask);
}

static bool amd_iommu_capable(enum iommu_cap cap)
{
        switch (cap) {
        case IOMMU_CAP_CACHE_COHERENCY:
                return true;
        case IOMMU_CAP_INTR_REMAP:
                return (irq_remapping_enabled == 1);
        case IOMMU_CAP_NOEXEC:
                return false;
        }

        return false;
}

static void amd_iommu_get_dm_regions(struct device *dev,
                                     struct list_head *head)
{
        struct unity_map_entry *entry;
        u16 devid;

        devid = get_device_id(dev);

        list_for_each_entry(entry, &amd_iommu_unity_map, list) {
                struct iommu_dm_region *region;

                if (devid < entry->devid_start || devid > entry->devid_end)
                        continue;

                region = kzalloc(sizeof(*region), GFP_KERNEL);
                if (!region) {
                        pr_err("Out of memory allocating dm-regions for %s\n",
                                dev_name(dev));
                        return;
                }

                region->start = entry->address_start;
                region->length = entry->address_end - entry->address_start;
                if (entry->prot & IOMMU_PROT_IR)
                        region->prot |= IOMMU_READ;
                if (entry->prot & IOMMU_PROT_IW)
                        region->prot |= IOMMU_WRITE;

                list_add_tail(&region->list, head);
        }
}

static void amd_iommu_put_dm_regions(struct device *dev,
                                     struct list_head *head)
{
        struct iommu_dm_region *entry, *next;

        list_for_each_entry_safe(entry, next, head, list)
                kfree(entry);
}

static const struct iommu_ops amd_iommu_ops = {
        .capable = amd_iommu_capable,
        .domain_alloc = amd_iommu_domain_alloc,
        .domain_free  = amd_iommu_domain_free,
        .attach_dev = amd_iommu_attach_device,
        .detach_dev = amd_iommu_detach_device,
        .map = amd_iommu_map,
        .unmap = amd_iommu_unmap,
        .map_sg = default_iommu_map_sg,
        .iova_to_phys = amd_iommu_iova_to_phys,
        .add_device = amd_iommu_add_device,
        .remove_device = amd_iommu_remove_device,
        .device_group = pci_device_group,
        .get_dm_regions = amd_iommu_get_dm_regions,
        .put_dm_regions = amd_iommu_put_dm_regions,
        .pgsize_bitmap  = AMD_IOMMU_PGSIZES,
};

/*****************************************************************************
 *
 * The next functions do a basic initialization of IOMMU for pass through
 * mode
 *
 * In passthrough mode the IOMMU is initialized and enabled but not used for
 * DMA-API translation.
 *
 *****************************************************************************/

/* IOMMUv2 specific functions */
int amd_iommu_register_ppr_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_register(&ppr_notifier, nb);
}
EXPORT_SYMBOL(amd_iommu_register_ppr_notifier);

int amd_iommu_unregister_ppr_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_unregister(&ppr_notifier, nb);
}
EXPORT_SYMBOL(amd_iommu_unregister_ppr_notifier);

void amd_iommu_domain_direct_map(struct iommu_domain *dom)
{
        struct protection_domain *domain = to_pdomain(dom);
        unsigned long flags;

        spin_lock_irqsave(&domain->lock, flags);

        /* Update data structure */
        domain->mode    = PAGE_MODE_NONE;
        domain->updated = true;

        /* Make changes visible to IOMMUs */
        update_domain(domain);

        /* Page-table is not visible to IOMMU anymore, so free it */
        free_pagetable(domain);

        spin_unlock_irqrestore(&domain->lock, flags);
}
EXPORT_SYMBOL(amd_iommu_domain_direct_map);

int amd_iommu_domain_enable_v2(struct iommu_domain *dom, int pasids)
{
        struct protection_domain *domain = to_pdomain(dom);
        unsigned long flags;
        int levels, ret;

        if (pasids <= 0 || pasids > (PASID_MASK + 1))
                return -EINVAL;

        /* Number of GCR3 table levels required */
        for (levels = 0; (pasids - 1) & ~0x1ff; pasids >>= 9)
                levels += 1;

        if (levels > amd_iommu_max_glx_val)
                return -EINVAL;

        spin_lock_irqsave(&domain->lock, flags);

        /*
         * Save us all sanity checks whether devices already in the
         * domain support IOMMUv2. Just force that the domain has no
         * devices attached when it is switched into IOMMUv2 mode.
         */
        ret = -EBUSY;
        if (domain->dev_cnt > 0 || domain->flags & PD_IOMMUV2_MASK)
                goto out;

        ret = -ENOMEM;
        domain->gcr3_tbl = (void *)get_zeroed_page(GFP_ATOMIC);
        if (domain->gcr3_tbl == NULL)
                goto out;

        domain->glx      = levels;
        domain->flags   |= PD_IOMMUV2_MASK;
        domain->updated  = true;

        update_domain(domain);

        ret = 0;

out:
        spin_unlock_irqrestore(&domain->lock, flags);

        return ret;
}
EXPORT_SYMBOL(amd_iommu_domain_enable_v2);

static int __flush_pasid(struct protection_domain *domain, int pasid,
                         u64 address, bool size)
{
        struct iommu_dev_data *dev_data;
        struct iommu_cmd cmd;
        int i, ret;

        if (!(domain->flags & PD_IOMMUV2_MASK))
                return -EINVAL;

        build_inv_iommu_pasid(&cmd, domain->id, pasid, address, size);

        /*
         * IOMMU TLB needs to be flushed before Device TLB to
         * prevent device TLB refill from IOMMU TLB
         */
        for (i = 0; i < amd_iommus_present; ++i) {
                if (domain->dev_iommu[i] == 0)
                        continue;

                ret = iommu_queue_command(amd_iommus[i], &cmd);
                if (ret != 0)
                        goto out;
        }

        /* Wait until IOMMU TLB flushes are complete */
        domain_flush_complete(domain);

        /* Now flush device TLBs */
        list_for_each_entry(dev_data, &domain->dev_list, list) {
                struct amd_iommu *iommu;
                int qdep;

                /*
                   There might be non-IOMMUv2 capable devices in an IOMMUv2
                 * domain.
                 */
                if (!dev_data->ats.enabled)
                        continue;

                qdep  = dev_data->ats.qdep;
                iommu = amd_iommu_rlookup_table[dev_data->devid];

                build_inv_iotlb_pasid(&cmd, dev_data->devid, pasid,
                                      qdep, address, size);

                ret = iommu_queue_command(iommu, &cmd);
                if (ret != 0)
                        goto out;
        }

        /* Wait until all device TLBs are flushed */
        domain_flush_complete(domain);

        ret = 0;

out:

        return ret;
}

static int __amd_iommu_flush_page(struct protection_domain *domain, int pasid,
                                  u64 address)
{
        INC_STATS_COUNTER(invalidate_iotlb);

        return __flush_pasid(domain, pasid, address, false);
}

int amd_iommu_flush_page(struct iommu_domain *dom, int pasid,
                         u64 address)
{
        struct protection_domain *domain = to_pdomain(dom);
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&domain->lock, flags);
        ret = __amd_iommu_flush_page(domain, pasid, address);
        spin_unlock_irqrestore(&domain->lock, flags);

        return ret;
}
EXPORT_SYMBOL(amd_iommu_flush_page);

static int __amd_iommu_flush_tlb(struct protection_domain *domain, int pasid)
{
        INC_STATS_COUNTER(invalidate_iotlb_all);

        return __flush_pasid(domain, pasid, CMD_INV_IOMMU_ALL_PAGES_ADDRESS,
                             true);
}

int amd_iommu_flush_tlb(struct iommu_domain *dom, int pasid)
{
        struct protection_domain *domain = to_pdomain(dom);
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&domain->lock, flags);
        ret = __amd_iommu_flush_tlb(domain, pasid);
        spin_unlock_irqrestore(&domain->lock, flags);

        return ret;
}
EXPORT_SYMBOL(amd_iommu_flush_tlb);

static u64 *__get_gcr3_pte(u64 *root, int level, int pasid, bool alloc)
{
        int index;
        u64 *pte;

        while (true) {

                index = (pasid >> (9 * level)) & 0x1ff;
                pte   = &root[index];

                if (level == 0)
                        break;

                if (!(*pte & GCR3_VALID)) {
                        if (!alloc)
                                return NULL;

                        root = (void *)get_zeroed_page(GFP_ATOMIC);
                        if (root == NULL)
                                return NULL;

                        *pte = __pa(root) | GCR3_VALID;
                }

                root = __va(*pte & PAGE_MASK);

                level -= 1;
        }

        return pte;
}

static int __set_gcr3(struct protection_domain *domain, int pasid,
                      unsigned long cr3)
{
        u64 *pte;

        if (domain->mode != PAGE_MODE_NONE)
                return -EINVAL;

        pte = __get_gcr3_pte(domain->gcr3_tbl, domain->glx, pasid, true);
        if (pte == NULL)
                return -ENOMEM;

        *pte = (cr3 & PAGE_MASK) | GCR3_VALID;

        return __amd_iommu_flush_tlb(domain, pasid);
}

static int __clear_gcr3(struct protection_domain *domain, int pasid)
{
        u64 *pte;

        if (domain->mode != PAGE_MODE_NONE)
                return -EINVAL;

        pte = __get_gcr3_pte(domain->gcr3_tbl, domain->glx, pasid, false);
        if (pte == NULL)
                return 0;

        *pte = 0;

        return __amd_iommu_flush_tlb(domain, pasid);
}

int amd_iommu_domain_set_gcr3(struct iommu_domain *dom, int pasid,
                              unsigned long cr3)
{
        struct protection_domain *domain = to_pdomain(dom);
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&domain->lock, flags);
        ret = __set_gcr3(domain, pasid, cr3);
        spin_unlock_irqrestore(&domain->lock, flags);

        return ret;
}
EXPORT_SYMBOL(amd_iommu_domain_set_gcr3);

int amd_iommu_domain_clear_gcr3(struct iommu_domain *dom, int pasid)
{
        struct protection_domain *domain = to_pdomain(dom);
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&domain->lock, flags);
        ret = __clear_gcr3(domain, pasid);
        spin_unlock_irqrestore(&domain->lock, flags);

        return ret;
}
EXPORT_SYMBOL(amd_iommu_domain_clear_gcr3);

int amd_iommu_complete_ppr(struct pci_dev *pdev, int pasid,
                           int status, int tag)
{
        struct iommu_dev_data *dev_data;
        struct amd_iommu *iommu;
        struct iommu_cmd cmd;

        INC_STATS_COUNTER(complete_ppr);

        dev_data = get_dev_data(&pdev->dev);
        iommu    = amd_iommu_rlookup_table[dev_data->devid];

        build_complete_ppr(&cmd, dev_data->devid, pasid, status,
                           tag, dev_data->pri_tlp);

        return iommu_queue_command(iommu, &cmd);
}
EXPORT_SYMBOL(amd_iommu_complete_ppr);

struct iommu_domain *amd_iommu_get_v2_domain(struct pci_dev *pdev)
{
        struct protection_domain *pdomain;

        pdomain = get_domain(&pdev->dev);
        if (IS_ERR(pdomain))
                return NULL;

        /* Only return IOMMUv2 domains */
        if (!(pdomain->flags & PD_IOMMUV2_MASK))
                return NULL;

        return &pdomain->domain;
}
EXPORT_SYMBOL(amd_iommu_get_v2_domain);

void amd_iommu_enable_device_erratum(struct pci_dev *pdev, u32 erratum)
{
        struct iommu_dev_data *dev_data;

        if (!amd_iommu_v2_supported())
                return;

        dev_data = get_dev_data(&pdev->dev);
        dev_data->errata |= (1 << erratum);
}
EXPORT_SYMBOL(amd_iommu_enable_device_erratum);

int amd_iommu_device_info(struct pci_dev *pdev,
                          struct amd_iommu_device_info *info)
{
        int max_pasids;
        int pos;

        if (pdev == NULL || info == NULL)
                return -EINVAL;

        if (!amd_iommu_v2_supported())
                return -EINVAL;

        memset(info, 0, sizeof(*info));

        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ATS);
        if (pos)
                info->flags |= AMD_IOMMU_DEVICE_FLAG_ATS_SUP;

        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
        if (pos)
                info->flags |= AMD_IOMMU_DEVICE_FLAG_PRI_SUP;

        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
        if (pos) {
                int features;

                max_pasids = 1 << (9 * (amd_iommu_max_glx_val + 1));
                max_pasids = min(max_pasids, (1 << 20));

                info->flags |= AMD_IOMMU_DEVICE_FLAG_PASID_SUP;
                info->max_pasids = min(pci_max_pasids(pdev), max_pasids);

                features = pci_pasid_features(pdev);
                if (features & PCI_PASID_CAP_EXEC)
                        info->flags |= AMD_IOMMU_DEVICE_FLAG_EXEC_SUP;
                if (features & PCI_PASID_CAP_PRIV)
                        info->flags |= AMD_IOMMU_DEVICE_FLAG_PRIV_SUP;
        }

        return 0;
}
EXPORT_SYMBOL(amd_iommu_device_info);

#ifdef CONFIG_IRQ_REMAP

/*****************************************************************************
 *
 * Interrupt Remapping Implementation
 *
 *****************************************************************************/

union irte {
        u32 val;
        struct {
                u32 valid       : 1,
                    no_fault    : 1,
                    int_type    : 3,
                    rq_eoi      : 1,
                    dm          : 1,
                    rsvd_1      : 1,
                    destination : 8,
                    vector      : 8,
                    rsvd_2      : 8;
        } fields;
};

struct irq_2_irte {
        u16 devid; /* Device ID for IRTE table */
        u16 index; /* Index into IRTE table*/
};

struct amd_ir_data {
        struct irq_2_irte                       irq_2_irte;
        union irte                              irte_entry;
        union {
                struct msi_msg                  msi_entry;
        };
};

static struct irq_chip amd_ir_chip;

#define DTE_IRQ_PHYS_ADDR_MASK  (((1ULL << 45)-1) << 6)
#define DTE_IRQ_REMAP_INTCTL    (2ULL << 60)
#define DTE_IRQ_TABLE_LEN       (8ULL << 1)
#define DTE_IRQ_REMAP_ENABLE    1ULL

static void set_dte_irq_entry(u16 devid, struct irq_remap_table *table)
{
        u64 dte;

        dte     = amd_iommu_dev_table[devid].data[2];
        dte     &= ~DTE_IRQ_PHYS_ADDR_MASK;
        dte     |= virt_to_phys(table->table);
        dte     |= DTE_IRQ_REMAP_INTCTL;
        dte     |= DTE_IRQ_TABLE_LEN;
        dte     |= DTE_IRQ_REMAP_ENABLE;

        amd_iommu_dev_table[devid].data[2] = dte;
}

#define IRTE_ALLOCATED (~1U)

static struct irq_remap_table *get_irq_table(u16 devid, bool ioapic)
{
        struct irq_remap_table *table = NULL;
        struct amd_iommu *iommu;
        unsigned long flags;
        u16 alias;

        write_lock_irqsave(&amd_iommu_devtable_lock, flags);

        iommu = amd_iommu_rlookup_table[devid];
        if (!iommu)
                goto out_unlock;

        table = irq_lookup_table[devid];
        if (table)
                goto out;

        alias = amd_iommu_alias_table[devid];
        table = irq_lookup_table[alias];
        if (table) {
                irq_lookup_table[devid] = table;
                set_dte_irq_entry(devid, table);
                iommu_flush_dte(iommu, devid);
                goto out;
        }

        /* Nothing there yet, allocate new irq remapping table */
        table = kzalloc(sizeof(*table), GFP_ATOMIC);
        if (!table)
                goto out;

        /* Initialize table spin-lock */
        spin_lock_init(&table->lock);

        if (ioapic)
                /* Keep the first 32 indexes free for IOAPIC interrupts */
                table->min_index = 32;

        table->table = kmem_cache_alloc(amd_iommu_irq_cache, GFP_ATOMIC);
        if (!table->table) {
                kfree(table);
                table = NULL;
                goto out;
        }

        memset(table->table, 0, MAX_IRQS_PER_TABLE * sizeof(u32));

        if (ioapic) {
                int i;

                for (i = 0; i < 32; ++i)
                        table->table[i] = IRTE_ALLOCATED;
        }

        irq_lookup_table[devid] = table;
        set_dte_irq_entry(devid, table);
        iommu_flush_dte(iommu, devid);
        if (devid != alias) {
                irq_lookup_table[alias] = table;
                set_dte_irq_entry(alias, table);
                iommu_flush_dte(iommu, alias);
        }

out:
        iommu_completion_wait(iommu);

out_unlock:
        write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);

        return table;
}

static int alloc_irq_index(u16 devid, int count)
{
        struct irq_remap_table *table;
        unsigned long flags;
        int index, c;

        table = get_irq_table(devid, false);
        if (!table)
                return -ENODEV;

        spin_lock_irqsave(&table->lock, flags);

        /* Scan table for free entries */
        for (c = 0, index = table->min_index;
             index < MAX_IRQS_PER_TABLE;
             ++index) {
                if (table->table[index] == 0)
                        c += 1;
                else
                        c = 0;

                if (c == count) {
                        for (; c != 0; --c)
                                table->table[index - c + 1] = IRTE_ALLOCATED;

                        index -= count - 1;
                        goto out;
                }
        }

        index = -ENOSPC;

out:
        spin_unlock_irqrestore(&table->lock, flags);

        return index;
}

static int modify_irte(u16 devid, int index, union irte irte)
{
        struct irq_remap_table *table;
        struct amd_iommu *iommu;
        unsigned long flags;

        iommu = amd_iommu_rlookup_table[devid];
        if (iommu == NULL)
                return -EINVAL;

        table = get_irq_table(devid, false);
        if (!table)
                return -ENOMEM;

        spin_lock_irqsave(&table->lock, flags);
        table->table[index] = irte.val;
        spin_unlock_irqrestore(&table->lock, flags);

        iommu_flush_irt(iommu, devid);
        iommu_completion_wait(iommu);

        return 0;
}

static void free_irte(u16 devid, int index)
{
        struct irq_remap_table *table;
        struct amd_iommu *iommu;
        unsigned long flags;

        iommu = amd_iommu_rlookup_table[devid];
        if (iommu == NULL)
                return;

        table = get_irq_table(devid, false);
        if (!table)
                return;

        spin_lock_irqsave(&table->lock, flags);
        table->table[index] = 0;
        spin_unlock_irqrestore(&table->lock, flags);

        iommu_flush_irt(iommu, devid);
        iommu_completion_wait(iommu);
}

static int get_devid(struct irq_alloc_info *info)
{
        int devid = -1;

        switch (info->type) {
        case X86_IRQ_ALLOC_TYPE_IOAPIC:
                devid     = get_ioapic_devid(info->ioapic_id);
                break;
        case X86_IRQ_ALLOC_TYPE_HPET:
                devid     = get_hpet_devid(info->hpet_id);
                break;
        case X86_IRQ_ALLOC_TYPE_MSI:
        case X86_IRQ_ALLOC_TYPE_MSIX:
                devid = get_device_id(&info->msi_dev->dev);
                break;
        default:
                BUG_ON(1);
                break;
        }

        return devid;
}

static struct irq_domain *get_ir_irq_domain(struct irq_alloc_info *info)
{
        struct amd_iommu *iommu;
        int devid;

        if (!info)
                return NULL;

        devid = get_devid(info);
        if (devid >= 0) {
                iommu = amd_iommu_rlookup_table[devid];
                if (iommu)
                        return iommu->ir_domain;
        }

        return NULL;
}

static struct irq_domain *get_irq_domain(struct irq_alloc_info *info)
{
        struct amd_iommu *iommu;
        int devid;

        if (!info)
                return NULL;

        switch (info->type) {
        case X86_IRQ_ALLOC_TYPE_MSI:
        case X86_IRQ_ALLOC_TYPE_MSIX:
                devid = get_device_id(&info->msi_dev->dev);
                iommu = amd_iommu_rlookup_table[devid];
                if (iommu)
                        return iommu->msi_domain;
                break;
        default:
                break;
        }

        return NULL;
}

struct irq_remap_ops amd_iommu_irq_ops = {
        .prepare                = amd_iommu_prepare,
        .enable                 = amd_iommu_enable,
        .disable                = amd_iommu_disable,
        .reenable               = amd_iommu_reenable,
        .enable_faulting        = amd_iommu_enable_faulting,
        .get_ir_irq_domain      = get_ir_irq_domain,
        .get_irq_domain         = get_irq_domain,
};

static void irq_remapping_prepare_irte(struct amd_ir_data *data,
                                       struct irq_cfg *irq_cfg,
                                       struct irq_alloc_info *info,
                                       int devid, int index, int sub_handle)
{
        struct irq_2_irte *irte_info = &data->irq_2_irte;
        struct msi_msg *msg = &data->msi_entry;
        union irte *irte = &data->irte_entry;
        struct IO_APIC_route_entry *entry;

        data->irq_2_irte.devid = devid;
        data->irq_2_irte.index = index + sub_handle;

        /* Setup IRTE for IOMMU */
        irte->val = 0;
        irte->fields.vector      = irq_cfg->vector;
        irte->fields.int_type    = apic->irq_delivery_mode;
        irte->fields.destination = irq_cfg->dest_apicid;
        irte->fields.dm          = apic->irq_dest_mode;
        irte->fields.valid       = 1;

        switch (info->type) {
        case X86_IRQ_ALLOC_TYPE_IOAPIC:
                /* Setup IOAPIC entry */
                entry = info->ioapic_entry;
                info->ioapic_entry = NULL;
                memset(entry, 0, sizeof(*entry));
                entry->vector        = index;
                entry->mask          = 0;
                entry->trigger       = info->ioapic_trigger;
                entry->polarity      = info->ioapic_polarity;
                /* Mask level triggered irqs. */
                if (info->ioapic_trigger)
                        entry->mask = 1;
                break;

        case X86_IRQ_ALLOC_TYPE_HPET:
        case X86_IRQ_ALLOC_TYPE_MSI:
        case X86_IRQ_ALLOC_TYPE_MSIX:
                msg->address_hi = MSI_ADDR_BASE_HI;
                msg->address_lo = MSI_ADDR_BASE_LO;
                msg->data = irte_info->index;
                break;

        default:
                BUG_ON(1);
                break;
        }
}

static int irq_remapping_alloc(struct irq_domain *domain, unsigned int virq,